Servicing MD, DC, & N. VA
Call Now 800-457-0945
For Consultation & Inspection Services




Media used to inscribe modern monumental works. May be composed of aluminum oxide, silicon carbine, steel shot, etc; Sand or powdered pumice stone, which is rubbed against a sculpture’s surface to create a smooth or polished effect.

Above-Grade Waterproofing

The prevention of water intrusion into the exposed parts of the dwelling above ground level through the use of materials or systems that are not exposed to hydrostatic pressure.

Absolute Humidity

The amount of water vapor present in a unit volume of air.


The accumulation of water or vapor drawn directly into the structure’s cells.


Each surface has a default emissivity and solar absorptivity. The solar absorptivity is the fraction of incoming solar energy that the surface absorbs. The absorptivity can be calculated by integrating the product of the spectral solar radiance striking the surface by the spectral emissivity (or 1.0-reflectance) of the surface. The absorptivity property determines the amount of incident solar energy absorbed.


Any material added to stucco, plaster or mortar which speeds up the natural set.

Acid Rain

A popular term referring to the deposition of wet (rain, snow, sleet, fog and cloud water, dew) and dry (acidifying particles and gases) acidic components. A more accurate term is “acid deposition”. Distilled water, which contains no carbon dioxide, has a neutral pH of 7. Liquids with a pH less than 7 are acidic, and those with a pH greater than 7 are basic. “Clean” or unpolluted rain has a slightly acidic pH of about 5.2, because carbon dioxide and water in the air react together to form carbonic acid, a weak acid (pH 5.6 in distilled water), but unpolluted rain also contains other chemicals.

H2O (l) + CO2 (g) → H2CO3 (aq)

The extra acidity in rain comes from the reaction of primary air pollutants, primarily sulfur oxides and nitrogen oxides, with water in the air to form strong acids (like sulfuric and nitric acid). The main sources of these pollutants are industrial power-generating plants and vehicles.

Active Zone

Refers to the depth of soil instability or movement, usually due to moisture variation. Typically soil movement is due to variations in moisture. Also called the Seasonal or Weather Effected Zone.

Adequate Watering

Watering sufficient to stop or arrest settlement brought about by soil shrinkage resulting from loss of moisture.


To cause two surfaces to be held together by adhesion, typically with asphalt or roofing cements in built-up roofing and with contact cements in some single-ply membranes. The sticking together of substances that are in contact with one another.


The property of a coating or sealant to bond to the surface to which it is applied.

Adhesive Failure

Loss of bond of a coating or sealant from the surface to which it is applied.


A brick or building material made of sun-dried earth and straw

AGCA (Associated General Contractors of America)

Is a national trade organization of qualified construction contractors and industry related companies dedicated to skill, integrity, and responsibility. The AGCA is the voice of the construction industry and is dedicated to improving the quality of construction and protecting the public.


An inert granular material such as natural sand, manufactured sand, gravel, crushed gravel, crushed stone, vermiculite, perlite, and air-cooled blast-furnace slag, which when bound together into a conglomerate mass by a matrix forms concrete or mortar. A surfacing material or ballast for a roof system. Aggregate can be rock, stone, crushed stone or slag, water-worn gravel, crushed lava rock or marble chips.


American Institute of Architects.

Alignment Notch

A cutout projection or slit on the sides or ends of shingles that act as guides in application to secure proper exposure.


A condition of paint or aged asphalt brought about by the loss of volatile oils and the oxidation caused by solar radiation. “Alligatoring” produces a pattern of cracks resembling an alligator hide and is ultimately the result of the limited tolerance of paint or asphalt to thermal expansion or contraction.

Allowable Load

The load which may be safely transmitted to a foundation member.

Ambient Temperature

The temperature of the air.

Anchor Pier or Pile

A pile or pier connected to a structure by one or more ties to furnish lateral support or to uplift. Also, a reaction pile or pier for load testing.


American National Standards Institute


The highest point on a joist or joist girder where the sloped chords meet. Also, Excellent Waterproofing Company based in Virginia / Maryland / D.C.

Application Rate

The quantity (volume or thickness) of material applied per unit area.

APP (Atactic Polypropylene) Modified

Asphalt based raw roofing, usually torch-applied.


A curved construction which spans an opening.


Member of an entablature that rests on the capitols of the columns or piers, and supports the frieze.


A person who designs buildings or other structures and has completed schooling in building design or similar subjects and is licensed by the state as an architect.


Unit of measure of length times width expressed in square inches.


Consisting of, or containing clay.


Internal frame or hidden support.

Artificial Stone

Simulated stone composite material.

ASCE (American Society of Civil Engineers)

Founded in 1852, is the oldest national professional engineering society in the United States. It is dedicated to the advancement of the individual civil engineer and the civil engineering profession through education.

ASD (Allowable Stress Design)

A structural design method whereby a structural element is designed so that the unit stresses computed under the action of working or service loads do not exceed specified allowable values.


Angled patterns in a straight line of stonework.

Ashlar Block

A square or rectangular block of building stone. Large finished stone block, which is set face bedded; often incorporated into facades of mausoleums, crypts, and historic masonry structures.

Aspect Ratio

For any rectangular configuration, the ratio of the lengths of the sides.


A bituminous compound, dark brown or black in color, used in the manufacture of asphalt roofing shingles.

Asphalt shingle

A shingle manufactured by coating a reinforcing material (felt or fibrous glass mat) with asphalt and having mineral granules on the side exposed to the weather.


Sculptural form made by assembling various shapes and materials.

ASTM (American Society for Testing and Materials)

An organization which has developed over 10,000 technical standards which are used by industries worldwide. A voluntary organization concerned with development of consensus standards, testing procedures and specifications.

Atmospheric Staining

Deposition of particulate matter such as soot.

Atmospheric Incrustation

A surface crust, formed by a reaction between calcium and acidic water to form calcium sulfate.


An opening or skylighted lobby through two or more floor levels other than an enclosed stairway, elevator, etc.


The world’s most popular computer-aided drafting software product for the personal computer in both DOS and windows by Autodesk, Inc. Anything that can be drawn on a drawing board can be drawn by AutoCAD.

Auxiliary Load

Any dynamic live loads such as cranes, monorails, and material handling systems.


The space immediately under the sloping roof of a house.


A conduit for carrying a large volume of flowing water.

If you have questions please call (877) 344-1155 or email sam@theFoundationExpert.com




The operation of replacing dirt removed in excavation. To fill an open excavation with excavated material. In Virginia and Maryland, traditional practice has been to backfill with excavated soil originally removed to accommodate the foundation construction. Building codes in various counties now prohibit the replacement of certain soils, such as clay and silt, without a mix of soils containing a minimum of 51% sand / gravel. Sand and gravel are soils which permit drainage whereas silty clays are soils which hold water, are shrink / swell type soils, and are the cause of many foundation problems such as cracked and bowed foundation walls, as well as a contributing factor to other problems such as water seepage into the home, due to hydrostatic pressure.


An excavation machine with a large bucket used for digging and back-filling around the exterior of the foundation in certain types of waterproofing processes.

Basement Waterproofing

The control of water to prevent flooding of basement floors.Refers to techniques used to prevent water from entering the basement of a house or other building. Effective below ground waterproofing will include both drainage and sealers. Waterproofing is needed anytime a structure is built at ground level or below ground. Waterproofing and drainage considerations are especially needed in cases where ground water is likely to build up in the soil and raise the water table. This higher water table causes hydrostatic pressure to be exerted underneath basement floors and against basement walls. Hydrostatic pressure forces water in through cracks in foundation walls, through opening caused by expansion and contraction of the footing-foundation wall joint and up through floor cracks. Hydrostatic pressure can cause major structural damage to foundation walls and is likely to contribute to mold, decay and other moisture related problems.

Exterior waterproofing prevents water from entering foundation walls therefore preventing the wicking and molding of building materials. Waterproofing a structure from the exterior is the only method the IBC (International Building Code) recognizes as adequate to prevent structural damage caused by water intrusion. Prior to the 1980’s much of the original exterior waterproofing was actually damp-proofing using a degradable asphalt-based covering. Today, however, Polymer products such as Tremco’s Paraseal membrane will completely waterproof an exterior foundation wall. This material has a half-life in the thousands of years which makes it ideal for a long-term exterior waterproofing solution. Asphalt and tar based compounds are affected by soil pH and break down after 10-20 years, thus making that type of waterproofing ineffective over time.


The solid rock layer under the surface of the soil.

Below Grade

Any part of the house or structure that is underground or beneath ground level.


A subsurface layer of earth suitable for supporting a structure.

Back surfacing

Fine mineral matter applied to the backside of shingles to keep them from sticking.


An elevated platform or seating space of an assembly room projecting from a wall of a building.


An anchoring material, such as aggregate or precast concrete pavers, which employs the force of gravity to hold (or assist in holding) single-ply roof membranes in place.

Ballast Roof

A roof which has selected material, such as crushed stone, placed on its surface to hold down the roof from wind forces.


A miniature column or other form of upright which, in a series, supports a railing or handrail.


A square or round piece of solid steel which is usually 6 inches or less in width.

Barrel Roof

A roof design which in cross section is arched. Consists of a continuous arch of semi-circular sections.


A dark, dense volcanic rock difficult to shape.

Base Coat

Scratch coat. First layer of infill.

Base & Block Foundation

This is a home that was built traditionally pre-1950. This home is built without a grade beam. The entire understructure depends on footings, or poured sonitube piers.

Base flashing

That portion of the flashing attached to or resting on the deck to direct the flow of water onto the roof covering.

Base Metal

The metal to be welded or cut.

Base Plate

A steel plate welded to the base of a column which distributes the column loads over an area of foundation large enough to prevent crushing of the concrete and usually secured by anchor bolts.

Base Ply

Is one layer of felt fastened to the deck over which a built-up roof is applied.

Basement (See History of Basements)

The substructure or foundation of a building. 2. The lowest habitable story of a building, usually below ground level. 3. Geology. A complex of undifferentiated igneous and metamorphic rocks underlying sedimentary strata. 4. Slang. The last place or lowest level, as in competitive standings.

A basement is one or more floors of a building that are either completely or partially below the ground floor. Slab-on-grade buildings do not have basements. Basements are typically used as a utility space for a building where such items as the furnace, water heater, car park, and air-conditioning system are located; so also are amenities such as the electrical distribution system, and cable television distribution point.

In British English the word ‘basement’ is used for underground floors of, for example, department stores, but is rarely used for a space below a house, and the word cellar is used to apply to any such large underground room.

Structurally, for houses, the basement walls typically form the foundation. In warmer climates, houses sometimes do not have basements because they are not necessary (although many still prefer them.) In colder climates, the foundation must be below the frost line. Unless constructed in very cold climates, the frost line is not so deep as to justify an entire level below the ground, although it is usually deep enough that a basement is the assumed standard.


1″x2″x4′ wood strips nailed to the roof, upon which the field tile hangs.


The distance between the main frames of a building.

BBC (Basic Building Code)

A minimum model regulatory code for the protection of public health, safety, welfare and property by regulating and controlling the design, construction, quality of materials, use, occupancy, location and maintenance of all buildings and structures within a jurisdiction.


A structural member, usually horizontal, whose main function is to carry loads transverse to its longitudinal axis. These loads usually cause bending of the beam member. Some types of beams are simple, continuous, and cantilever.


A structural member whose main function is to carry loads both parallel and transverse to its longitudinal axis.


1) The distance that the bearing shoe or seat of a joist or joist girder extends over its masonry, concrete, or steel support

2) A structural support, usually a beam or wall, that is designed by the specifying professional to carry reactions to the foundation

Bearing Plate

The steel plate used for a joist or joist girder to bear on when they are supported by masonry or concrete supports. This plate transfers the joist reaction to the supporting structure and must be sized accordingly.

Bearing Wall

A wall which is supporting any vertical loads i2n addition to its own weight.

Bell Bottom Pier

A Bell Bottom pier is a vertical structural support built to support concrete slab foundations and is built of concrete and steel rebar. Its name is derived from the bottom of the pier, which resembles a bell and provides a greater area of support for the pier and the concrete slab above it.


An applied sealant in a joint irrespective of the method of application, such as caulking bead, glazing bead, etc. A jutting horizontal protrusion nears the top of a decorative pillar.

Bearing Capacity Of Soil

The maximum pressure which can be applied to a soil mass without causing shear failure. The pressure or stress is created by applied loads and transmitted to the soil by the foundation.


In rock, the flat surface of a stone parallel to its stratification.

Bed Joint

The horizontal layer of mortar on which a masonry unit is laid.

Bending Moment

The condition in the analysis of the internal stresses across the cross section of a member when it is subjected to forces which cause it to bend.

Bending Stress

Is zero at the neutral axis and assumed to increase linearly to a maximum at the outer fibers of the section.

Formula in the elastic range Bending stress (in psi)=(M * c)/I, where ‘M’ is the bending moment at the section in in-lbs, ‘I’ is the moment of inertia of the section in inches^4, and ‘c’ is the distance from the neutral axis to the point at which the stress is desired in inches.


The plane of beam or joist girder members which support loads and the columns which support these members.

Bevel Cut

A single cut made at an angle to the member length.

BG-Type Joist Girder

A type of Joist Girder where joists are located at all panel points where vertical webs and diagonal webs intersect the top chord.


The phenomenon whereby a perfectly straight member may either assume a deflected position, deflect then twist out of plane, or may remain in an undeflected configuration.

Biological Activity

Algae or Lichen growth visible on the stones surface.


A method of cleaning or of roughening a surface by a forceable stream of sharp angular abrasive.

Blind Pinning

To place hidden support in a structure or monument to join sections together. May be employed during construction or as a repair technique. Pinning should be of a non-ferrous metal or fiberglass material.


Spalling of the second degree.


A concrete masonry unit made with fine aggregate and cement that is shaped in a mold.

Blue Print

Also called a blue line. Is a copy of an architectural or other drawing made by a special machine usually on white paper with the lines and text being a blue color.

BOCA (Building Officials and Code Administrators International, Inc.). 2. A minimum model regulatory code for the protection of public health, safety, welfare and property by regulating and controlling the design, construction, quality of materials, use, occupancy, location and maintenance of all buildings and structures within a jurisdiction. Its serves primarily the North Central and Northeast United States.


A hard fine-grained stone often used for mainly for walkways or patios.

Bolted Splice

The connection between two structural members joined at their ends by bolting to form a single, longer member.


The property of a hardened mortar that knits the masonry units together; The overlapping of masonry units to make them stronger or more pleasing in appearance.

Bond Beam

The top course of block of a masonry wall filled with concrete and reinforcing steel and used to support roof loads.

Border Design

The carving which often ornamented the side panels of historic tablet stones.

Boxed Column

A supporting column that is square shaped as opposed to circular. It is most often found on a Doric capital.

Box Tomb

A crypt style monument with no body interred inside. The interior is a hallow cavity.

Braced Frame

A frame which resists lateral loads by the use of diagonal bracing, K-braces, or other system of bracing.


A structural support attached to a column or wall on which to fasten another structural member.

Bridge Crane

A lifting system which has a hoist that moves laterally on a beam or other member which then in turn moves longitudinally on a runway made of beams and rails.


In general, is a member connected to a joist to brace it from lateral movement.

Bridging Anchor

An angle or bent plate attached to a wall where the bridging will be attached or anchored, either by welding or bolting. The ends of all bridging lines terminating at walls or beams shall be anchored thereto.

Bridging Clip

A small piece of angle or plate with a hole or slot that is welded to the top and bottom chord angles so that bridging may be attached.

Bridging Diagram

A diagram of the profile of a joist used to show the number and location of the rows of bridging.

Brittle Fracture

The tearing or splitting of a member with little or no prior ductile deformation.

BTU (British Thermal Unit)

The amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.

Buckling Load

The load at which a straight member under compression transfers to a deflected position.


Any structure used for support or for shelter.

Building Code

Regulations established by a recognized agency describing design loads, procedures, quality of materials, and construction details for buildings for the protection of the public.

Building Designer

A registered architect or registered engineer who is responsible for the design of a structure.

Building Official

The officer or other authority which has the duty of administration and enforcement of a building code.

Built-Up Roof

A type of roof composed of two or more layers of alternating felt, tar and asphalt.

Built-Up Section

A structural member made up from individual flat plates welded together or any structural metal elements that are welded or bolted together.

Butt Plate

The end plate of a structural member usually used to rest or butt against a like plate of another member in forming a connection.

Builder Piers

When the grade beam on a Pier & Beam home is poured, builder piers are poured beforehand at a spacing of 4-8 feet apart and at an average of 3-4 feet down. These piers assist in holding the grade beam in place. Due to their low level of placement, they can fail and additional pier supports become required.


An alloy of copper and zinc that is malleable and stronger then copper.

Brick Masonry

A type of construction that has units of baked clay or shale of uniform size, small enough to be placed with one hand, laid in courses with mortar joints to form walls, pillars, and various structures.

Brick Set

A wide-blade chisel used for cutting bricks and blocks.


An alloy of approximately 90 percent copper and 10 percent tin, which contains small amounts of other metals such as lead and zinc. Hard and durable, it is one of the most commonly used materials for sculptural works.

Brown Coat

The second coat of stucco in a three-coat work.


Sandstone. Can be reddish, light brown- blond, and dark brown. Found throughout New England, East Middletown Connecticut, which is now Portland, contained the largest number of brownstone quarries in the world, during the 1800s.


To apply a quantity of mortar onto a brick, block or stone, often on the small end,

prior to it being laid.


Often associated with Gothic architecture. The out-jutting, or thickening of a wall to support an overhead beam or roof arch. Added support to oppose horizontal forces on tall walls.

Below Grade

The portion of a building that is below ground level. Sub soil.


Any of various mixtures of hydrocarbons occurring naturally or obtained through the distillation of coal or petroleum.


Mixtures of various colored granules found on the one face of mineral-surfaced roofing.

Blind nailing

Nails driven in such a way that the heads are not visible.


An enclosed raised spot evident on the surface of a building. They are mainly caused by the expansion of trapped air, water vapor, moisture or other gases.

Board Stock Insulation

A board stock insulation has a core of one of the following materials APA-rated OSB; asphalt/glass; glass-based; gypsum; mineral wool; perlite; Polyisocyanurate/polyurethane; expanded polystyrene foam (EPS); extruded polystyrene foam (XPS); or wood fiber. The material, the number of board stock layers, and the position of the product within the assembly determine whether it will be classified as an insulation, a cover board, or a thermal barrier.

Bond breaker

A layer or coating that is applied to a specific area of a substrate, such that, when a subsequent layer or coating is applied over the bond breaker, it will not bond or adhere in that area.

Boston lap

A method of finishing the ridge of a shingle course, using overlapping vertical joints.

Bowstring roof

A roof constructed with curved timber trusses and horizontal tie-beams connected by light diagonal lattices of wood.

Built-up roof (BUR)

An outer covering of a comparatively flat roof, consisting of several layers of saturated felt. As laid, each layer is mopped with hot tar or asphalt. The top layer is finished with a mineral or rock covering and a special coating.


A package of shingles. There are 3, 4 or 5 bundles per square.

Butt edge

The lower edge of the shingle tabs.

Butterfly Roof

A roof assembly which pitches sharply from either side toward the center.

Brick ledge

Part of the foundation wall where the base layer of brick veneer is placed.

Brick lintel

Angle iron on which brick is placed. Used above windows, doors, and other openings.

If you have questions please call (877) 344-1155 or email sam@theFoundationExpert.com


“C” Section

A structural member cold-formed from sheet steel in the shape of a block “C” which can be used by itself or back to back with another C Section.


Abbreviation for Computer-Aided Drafting.

Caisson Or Caisson Pile

A large-diameter shaft hand- or machine-excavated to bearing stratum inside a protective casing. The shaft may require a cutting shoe to penetrate obstructions.


Consisting of, or containing, calcium carbonate or carbonate of lime.

Catch basin

The inlet used to take water in to direct them into a 4″ or 6″ pipe when used to control water. These are usually 9″ x9 ” to 12″ x 12″.


Burning Enough heat to cause disintegration, or total fusion.


A rock forming mineral, calcite is found in limestone and seashells. It is very common on the earth’s surface, as it dissolves in water and grows anywhere that water can reach.


A soft, silver- white chemical element found in limestone, marble and chalks.


A measuring instrument that has two parallel jaws, which move and then hold in place, in order to transfer a specific size.


A mechanical instrument usually having a pair of pivoted legs adjustable to any distance and used to measure thickness, distances between surfaces, and any internal or external diameter which is inaccessible with a scale.


Camber is an upward curvature of the chords of a joist or joist girder induced during shop fabrication to compensate for deflection due to loading conditions. Note, this is in addition to the pitch of the top chord.


A projecting member that is supported at one end only.

Cant Strip

A deck accessory which is a short piece of gage steel used at 45 degrees where a wall or parapet meets the end of deck.

Canted Seat

A seat which is sloped perpendicular to the member which most joist manufactures do not do. Usually the steel contractor furnishes a bent plate shim to provide level bearing for the seat.


The part of a member that extends freely over a support which is not supported at its end.


The top cement surface on a masonry structure.

Cap flashing

The portion of the flashing that is built into a vertical surface to prevent water seepage behind the base flashing. Cap flashing overlaps the base flashing.


capillary motion

Capillary Action or wicking is the ability of a substance to draw another substance into it. Capillary action describes the attraction of water molecules to soil particles and is responsible for moving groundwater from the wetter areas to the area surrounding your house. Capillary action also describes the wick-like migration of water into the porous walls and floor in the same manner as water is drawn into a sponge. Capillary action actually is the dynamic by which water will actually move against gravity or the path of least resistance, moving sideways and upwards into the foundation walls and floors of a home. (See Causes and Solutions)


The upper-most member of a column or pilaster. It often supports an architrave or entablature, and is often decorated.

Cap Plate

A steel plate welded to the top of a column which a joist, joist girder, or other structural member can bear on.

Cap Sheets

In roofing, one to four plies of felt bonded and top coated with bitumen that is laid over an existing roof as a treatment for defective roofs.


Stone on top of a monument or wall.


The form produced by filling a mould. The positive form.

Cast Iron

Iron made in a mold.


Suspended structural framing used to provide access to and between areas below a roof and above a floor.


To seal up crevices with some flexible material. To fill a joint with mastic or asphalt cement to prevent leaks.

Caulking of Exterior Seals

A Process used to seal window and door openings where leaks have occurred due to foundation settlement. Special care is taken in removing all old and deteriorated caulking from window and door openings, and is then replaced with rubberized silicone weather-resistant caulk.

  • When a structure settles and/or shifts, the veneer pulls away from window and door openings resulting in energy loss.
  • Separations in window and door openings also allows damage from outside elements and could contribute to serious damage to structural framework over a period of time.

Cavity Wall

A wall with an air space behind it, such as in a box tomb.

Ceiling Extension

Is similar to a bottom chord extension except that only one angle of the joist bottom chord is extended from the first bottom chord panel point towards the end of the joist.


The binding material which holds the aggregates together, in concrete and mortar, binding them into a solid mass. Derived from the Latin “caedere” ( to cut ), and signifies any substance used to adhere objects together. Cement is made by heating limestone with small quantities of other materials (such as clay) to 1450°C in a kiln. The resulting hard substance, called ‘clinker’, is then ground with a small amount of gypsum into a powder to make ‘Ordinary Portland Cement’, the most commonly used type of cement (often referred to as OPC).

Portland cement

Portland cement is a basic ingredient of concrete, mortar and most non-specialty grout. The most common use for Portland cement is in the production of concrete. Concrete is a composite material consisting of aggregate (gravel and sand), cement, and water. As a construction material, concrete can be cast in almost any shape desired, and once hardened, can become a structural (load bearing) element. Portland cement may be gray or white.

Portland cement blends

These are often available as inter-ground mixtures from cement manufacturers, but similar formulations are often also mixed from the ground components at the concrete mixing plant. Portland Blast furnace Cement contains up to 70% ground granulated blast furnace slag, with the rest Portland clinker and a little gypsum. All compositions produce high ultimate strength, but as slag content is increased, early strength is reduced, while sulfate resistance increases and heat evolution diminishes. Used as an economic alternative to Portland sulfate-resisting and low-heat cements.

Portland Flyash Cement contains up to 30% fly ash. The flyash is pozzolanic, so that ultimate strength is maintained. Because flyash addition allows a lower concrete water content, early strength can also be maintained. Where good quality cheap flyash is available, this can be an economic alternative to ordinary Portland cement.

Portland Pozzolan Cement includes fly ash cement, since fly ash is a pozzolan, but also includes cements made from other natural or artificial pozzolans. In countries where volcanic ashes are available (e.g. Italy, Chile, Mexico, the Philippines) these cements are often the most common form in use.

Portland Silica Fume Cement Addition of silica fume can yield exceptionally high strengths, and cements containing 5-20% silica fume are occasionally produced. However, silica fume is more usually added to Portland cement at the concrete mixer.

Masonry Cements are used for preparing bricklaying mortars and stuccos, and must not be used in concrete. They are usually complex proprietary

formulations containing Portland clinker and a number of other ingredients that may include limestone, hydrated lime, air entrainers, retarders, waterproofers and coloring agents. They are formulated to yield workable mortars that allow rapid and consistent masonry work. Subtle variations of Masonry cement in the US are Plastic Cements and Stucco Cements. These are designed to produce controlled bond with masonry blocks.

Expansive Cements contain, in addition to Portland clinker, expansive clinkers (usually sulfoaluminate clinkers), and are designed to offset the effects of drying shrinkage that is normally encountered with hydraulic cements. This allows large floor slabs (up to 60 m square) to be prepared without contraction joints.

White blended cements may be made using white clinker and white supplementary materials such as high-purity metakaolin. Colored cements are used for decorative purposes. In some standards, the addition of pigments to produce “colored Portland cement” is allowed. In other standards (e.g. ASTM), pigments are not allowed constituents of Portland cement, and colored cements are sold as “blended hydraulic cements”.

Very finely ground cements are made from mixtures of cement with sand or with slag or other Pozzolan type minerals which are extremely finely ground. Such cements can have the same physical characteristics as normal cement but with 50% less cement particularly due to their increased surface area for the chemical reaction. Even with intensive grinding they can use up to 50% less energy to fabricate than ordinary Portland cements.

Non-Portland hydraulic cements

Pozzolan-lime cements. Mixtures of ground pozzolan and lime are the cements used by the Romans, and are to be found in Roman structures still standing (e.g. the Pantheon in Rome). They develop strength slowly, but their ultimate strength can be very high. The hydration products that produce strength are essentially the same as those produced by Portland cement.

Slag-lime cements. Ground granulated blast furnace slag is not hydraulic on its own, but is “activated” by addition of alkalis, most economically using lime. They are similar to pozzolan lime cements in their properties. Only granulated slag (i.e. water-quenched, glassy slag) is effective as a cement component.

Supersulfated cements. These contain about 80% ground granulated blast furnace slag, 15% gypsum or anhydrite and a little Portland clinker or lime as an activator. They produce strength by formation of ettringite, with strength growth similar to a slow Portland cement. They exhibit good resistance to aggressive agents, including sulfate.

Calcium aluminate cements are hydraulic cements made primarily from limestone and bauxite. The active ingredients are monocalcium aluminate CaAl2O4 (CA in Cement chemist notation) and Mayenite Ca12Al14O33 (C12A7 in CCN). Strength forms by hydration to calcium aluminate hydrates. They are well-adapted for use in refractory (high-temperature resistant) concretes, e.g. for furnace linings.

Calcium sulfoaluminate cements are made from clinkers that include ye’elimite (Ca4(AlO2)6SO4 or C4A3bar mathrm{S} in Cement chemist’s notation) as a primary phase. They are used in expansive cements, in ultra-high early strength cements, and in “low-energy” cements. Hydration produces ettringite, and specialized physical properties (such as expansion or rapid reaction) are obtained by adjustment of the availability of calcium and sulfate ions. Their use as a low-energy alternative to Portland cement has been pioneered in China, where several million tons per year are produced. Energy requirements are lower because of the lower kiln temperatures required for reaction, and the lower amount of limestone (which must be endothermically decarbonated) in the mix. In addition, the lower limestone content and lower fuel consumption leads to a CO2 emission around half that associated with Portland clinker. However, SO2 emissions are usually significantly higher.

“Natural” Cements correspond to certain cements of the pre-Portland era, produced by burning argillaceous limestones at moderate temperatures. The level of clay components in the limestone (around 30-35%) is such that large amounts of belite (the low-early strength, high-late strength mineral in Portland cement) are formed without the formation of excessive amounts free lime. As with any natural material, such cements have very variable properties.

Geopolymer cements are made from mixtures of water-soluble alkali metal silicates and aluminosilicate mineral powders such as fly ash and metakaolin.


Greek for empty tomb. A monument to honor a deceased who is buried elsewhere, or whose body was never found, as in “drowned at sea”.


The final process of finishing a bronze cast once it has cooled from the furnace. Chisels and punches are used to remove imperfections, and the surface is polished or smoothed down.


Silky appearance on the surface of a mineral, known as “cat’s eye” effect.


The beveled surface formed by cutting off the edge or corner, from a squared surface, at a 45% angle.


A steel tool used for shaping stone, wood or metal. It is often held at an angle and struck with a mallet to force the sharp cutting edge along the surface being carved.

Centerline Span (or Center-to-Center)

A theoretical span definition which is the distance between the actual centerlines of a beam, column, joist, or joist girder.


The point in a member at the intersection of two perpendicular axes so located that the moments of the areas on opposite sides of an axis about that axis is zero.

Certified Welder

A welder who has been certified by a competent experienced welding inspector or a recognized testing facility in the field of welding. The welder must be certified to make certain welds under qualified procedures. The welder must be qualified for each position, type weld, electrode, and thickness of base metal that is to be welded in the shop or field.

Change Order

A written document which modifies the plans, specifications, or price of a construction contract.


A hot rolled structural shape the looks like “[“.

Check Valve

A device that permits water flow in only one direction and is commonly installed in the sump pump discharge line.


The two angle top or bottom member of a joist or joist girder, usually with a gap between the angles.


The exterior covering of the structural members of a building.

Class “A”

The highest fire-resistance rating for roofing as per ASTM E-108. Indicates roofing is able to withstand severe exposure to fire originating from sources outside the building.

Class “B”

Fire-resistance rating that indicates roofing materials are able to withstand moderate exposure to fire originating from sources outside the building.

Class “C”

Fire-resistance rating that indicates roofing materials are able to withstand light exposure to fire originating from sources outside the building.


Fragments in sedimentary rocks that originally formed part of other rocks.


A soil that has the finest possible particles, usually smaller than 1/10,00 in (2.5X10-4 cm) in diameter, and often possesses the capacity for extreme volume changes with differential access to water.

The finest-grain particles in a sediment, soil, or rock. Clay is finer than silt, characterized by a grain size of less than approximately 4 micrometers. However, the term clay can also refer to a rock or a deposit containing a large component of clay-size material. Thus clay can be composed of any inorganic materials, such as clay minerals, allophane, quartz, feldspar, zeolites, and iron hydroxides, that possess a sufficiently fine grain size. Most clays, however, are composed primarily of clay minerals.

Although the composition of clays can vary, clays can share several properties that result from their fine particle size. These properties include plasticity when wet, the ability to form colloidal suspensions when dispersed in water, and the tendency to flocculate (clump together) and settle out in saline water.

Clays, together with organic matter, water, and air, are one of the four main components of soil. Clays can form directly in a soil by precipitation from solution (neoformed clays); they can form from the partial alteration of clays already present in the soil (transformed clays); or they can be inherited from the underlying bedrock or from sediments transported into the soil by wind, water, or ice (inherited clays).

The type of clays neoformed in a soil depends on the composition of the soil solution, which in turn is a function of climate, drainage, original rock type, vegetation, and time. Generally, neoformed clays that have undergone intense leaching, such as soils formed under wet, tropical climates, are composed of the least soluble elements, such as ferric iron, aluminum, and silicon. These soils contain clays such as gibbsite, kaolinite, goethite, and amorphous oxides and hydroxides of aluminum and iron. Clays formed in soils that are found in dry climates or in soils that are poorly drained can contain more soluble elements, such as sodium, potassium, calcium, and magnesium, in addition to the least soluble elements. These soils contain clays such as smectite, chlorite, and illite, and generally are more fertile than those formed under intense leaching conditions.

Examples of clays formed by the transformation of other clays in a soil include soil chlorite and soil vermiculite, the first formed by the precipitation of aluminum hydroxide in smectite interlayers, and the second formed by the leaching of interlayer potassium from illite. Examples of inherited clays in a soil are illite and chlorite-containing soils formed on shales composed of these minerals.

Clays also occur abundantly in sediments and sedimentary rocks. For example, clays are a major component of many marine sediments. These clays generally are inherited from adjacent continents, and are carried to the ocean by rivers and wind, although some clays (such as smectite and glauconite) are neoformed abundantly in the ocean. Hydrothermal clays can form abundantly where rock has been in contact with hot water or steam. Illite and chlorite, for example, form during the deep burial of sediments, and smectite and chlorite form by the reaction of hot, circulating waters at ocean ridges.

Various clays possess special properties which make them important industrially. For example, bentonite, a smectite formed primarily from the alteration of volcanic ash, swells; is readily dispersible in water; and possesses strong absorptive powers, including a high cation exchange capacity. These properties lead to uses in drilling muds, as catalysts and ion exchangers, as fillers and absorbents in food and cosmetics, and as binders for taxonite and fertilizers. Other important uses for clays include the manufacture of brick, ceramics, molding sands, decolorizers, detergents and soaps, medicines, adhesives, liners for ponds and landfills, lightweight aggregate, desiccants, molecular sieves, pigments, greases, paints, plasticizing agents, emulsifying, suspending, and stabilizing agents, and many other products.

Clay Bearing Failure

The result of expansive soils exerting non-uniform pressure against a constant downward loading. Such loading causes a pier to deviate further from vertical until the pier can no longer support the structural load.

Claw Chisel

A chisel with its cutting edge divided into two or more prongs.

Clear Span

The actual clear distance or opening between supports for a structural member, i.e., the distance between walls or the distance between the edges of flanges of beams.


The way a mineral breaks along a plane according to its atomic structure. In rocks, the way it splits along the bedding planes or striations.


An upward extension of enclosed daylighted space created by carrying a setback vertical, windowed wall up and through the roof slope.


A U-shaped yoke with internal threads in one end which can be attached to a threaded rod and the other end a connection with a hole used for a pin or bolt attachment.

Clip Angle

A structural angle which attaches to the side of a wall, column, beam, etc. where a joist, joist girder, or other structural member bears.

Closure Brick

A partial brick that is cut to fit into a place to complete a course.

Closure Strip

A floor deck accessory made of gage metal which is placed over the ends of deck so that concrete cannot run out of the flutes of the deck.

Coefficient of (Linear) Expansion

The change in length, per unit, for a change of one degree of temperature.


The process of forming a structural section by bending sheet or strip steel in roll-forming machines without the use of heat.

Collateral Load

All additional dead loads other than the weight of the building, such as sprinklers, pipes, ceilings, and mechanical or electrical components.

Coloring Agents

Colored aggregates or iron oxides ground finer then the cement.


Is a main vertical member carrying axial loads, which can be combined with bending and shear, from the main roof beams or girders to the foundation. These structural members carry loads parallel to its longitudinal axis. A tall, vertical, cylindrical member, most often associated, with a classical capitol.

Column Curve

A curve which shows the relationship between axial column strength and slenderness ratio.


A ratchet hand winch.

Compact Section

A steel section whose flanges must be continuously connected to the webs and the width-thickness ratios of its compression element cannot exceed the limiting width-thickness ratios designated in the AISC Manual.

Composite Beam

A steel beam and a concrete slab connected, usually by shear stud connectors, so that they act together to resist the load on the beam.

Composite Stone

Artificial stone formulated to match existing substrate in stone conservation.


A condition caused by the action of squeezing or shortening of a component.

Compression Member

Any member in which the primary stress is longitudinal compression.

Compressive Strength

The power to resist crushing under pressure. Contrasted by tensile strength, the power to resist the action of forces pulling apart.

Concentrated Load

A single load or force that has such a small contact area as to be negligible compared with the entire surface area of the supporting member and applied at a certain point on the structure.


A artificial stone made by mixing cement and sand with gravel, broken stone, or other aggregate. These materials must be mixed with sufficient water to

cause the cement to set and bind the entire mass. The preferred material for all modern monuments foundations.

Regular concrete

Regular concrete is the lay term describing concrete that is produced by following the mixing instructions that are commonly published on packets of cement, typically using sand or other common material as the aggregate, and often mixed in improvised containers. This concrete can be produced to yield a varying strength from about 10 MPa (1450 psi) to about 40 MPa (5800 psi), depending on the purpose, ranging from blinding to structural concrete respectively. Many types of pre-mixed concrete are available which include powdered cement mixed with an aggregate, needing only water.

Typically, a batch of concrete can be made by using 1 part Portland cement, 2 parts dry sand, 3 parts dry stone, 1/2 part water. The parts are in terms of weight – not volume. For example, 1-cubic-foot (0.028 m3) of concrete would be made using 22 lb (10.0 kg) cement, 10 lb (4.5 kg) water, 41 lb (19 kg) dry sand, 70 lb (32 kg) dry stone (1/2″ to 3/4″ stone). This would make 1-cubic-foot (0.028 m3) of concrete and would weigh about 143 lb (65 kg). The sand should be mortar or brick sand (washed and filtered if possible) and the stone should be washed if possible. Organic materials (leaves, twigs, etc) should be removed from the sand and stone to ensure the highest strength.

High-strength concrete

High-strength concrete has a compressive strength generally greater than 6,000 pounds per square inch (40 MPa = 5800 psi). High-strength concrete is made by lowering the water-cement (W/C) ratio to 0.35 or lower. Often silica fume is added to prevent the formation of free calcium hydroxide crystals in the cement matrix, which might reduce the strength at the cement-aggregate bond.

Low W/C ratios and the use of silica fume make concrete mixes significantly less workable, which is particularly likely to be a problem in high-strength concrete applications where dense rebar cages are likely to be used. To compensate for the reduced workability, superplasticizers are commonly added to high-strength mixtures. Aggregate must be selected carefully for high-strength mixes, as weaker aggregates may not be strong enough to resist the loads imposed on the concrete and cause failure to start in the aggregate rather than in the matrix or at a void, as normally occurs in regular concrete. In some applications of high-strength concrete the design criterion is the elastic modulus rather than the ultimate compressive strength.

High-performance concrete

High-performance concrete (HPC) is a relatively new term used to describe concrete that conforms to a set of standards above those of the most common applications, but not limited to strength. While all high-strength concrete is also high-performance, not all high-performance concrete is high-strength.

Self-consolidating concretes

During the 1980s a number of countries including Japan, Sweden and France developed concretes that are self-compacting, known as self-consolidating concrete in the United States. This self-consolidating concrete (SCCs) is characterized by

  • extreme fluidity as measured by flow, typically between 650-750 mm on a flow table, rather than slump(height)
  • no need for vibrators to compact the concrete
  • placement being easier.
  • no bleed water, or aggregate segregation
  • Increased Liquid Head Pressure, Can be detrimental to Safety and workmanship

SCC can save up to 50% in labor costs due to 80% faster pouring and reduced wear and tear on formwork. As of 2005, self-consolidating concretes account for 10-15% of concrete sales in some European countries. In the US precast concrete industry, SCC represents over 75% of concrete production. 38 departments of transportation in the US accept the use of SCC for road and bridge projects. This emerging technology is made possible by the use of polycarboxylates plasticizer instead of older naphthalene based polymers, and viscosity modifiers to address aggregate segregation.


Shotcrete (also known by the trade name Gunite) uses compressed air to shoot concrete onto (or into) a frame or structure. Shotcrete is frequently used against vertical soil or rock surfaces, as it eliminates the need for formwork. It is sometimes used for rock support, especially in tunneling. Shotcrete is also used for applications where seepage is an issue to limit the amount of water entering a construction site due to a high water table or other subterranean sources. This type of concrete is often used as a quick fix for weathering for loose soil types in construction zones.

There are two application methods for shotcrete.

  • dry-mix – the dry mixture of cement and aggregates is filled into the machine and conveyed with compressed air through the hoses. The water needed for the hydration is added at the nozzle.
  • wet-mix – the mixes are prepared with all necessary water for hydration. The mixes are pumped through the hoses. At the nozzle compressed air is added for spraying.

For both methods additives such as accelerators and fiber reinforcement may be used.

Pervious concrete

Pervious concrete contains a network of holes or voids, to allow air or water to move through the concrete. This allows water to drain naturally through it, and can both remove the normal surface-water drainage infrastructure, and allow replenishment of groundwater when conventional concrete does not.

It is formed by leaving out some or all of the fine aggregate (fines), the remaining large aggregate then is bound by a relatively small amount of Portland Cement. When set, typically between 15% and 25% of the concrete volume are voids, allowing water to drain at around 5 gal/ft²/ min or 200 L/m²/min) through the concrete.


Pervious is installed by being poured into forms, then screeded off, to level (not smooth) the surface, then packed or tamped into place. Due to the low water content and air permeability, within 5-15 minutes of tamping, the concrete must be covered with a 6-mil poly plastic, or it will dry out prematurely and not properly hydrate and cure.


Pervious can significantly reduce noise, by allowing air to be squeezed between vehicle tires and the roadway to escape. Unfortunately this product cannot be used on major state highways yet due to the high psi ratings required by most U.S. states. Pervious has been tested up to 4500psi so far.

Cellular concrete

Aerated concrete produced by the addition of an air entraining agent to the concrete (or a lightweight aggregate like expanded clay pellets or cork granules and vermiculite) is sometimes called Cellular concrete.

Cork-cement composites

Waste Cork granules are obtained during production of bottle stoppers from the treated bark of Cork oak. These granules have a density of about 300 kg/m³, lower than most lightweight aggregates used for making lightweight concrete. Cork granules do not significantly influence cement hydration, but cork dust may. Cork cement composites have several advantages over standard concrete, such as lower thermal conductivities, lower densities and good energy absorption characteristics. These composites can be made of density from 400 to 1500 kg/m³, compressive strength from 1 to 26 MPa, and flexural strength from 0.5 to 4.0 MPa.

Roller-compacted concrete

Roller-compacted concrete, sometimes called rollcrete, is a low-cement-content stiff concrete placed using techniques borrowed from earthmoving and paving work. The concrete is placed on the surface to be covered, and is compacted in place using large heavy rollers typically used in earthwork. The concrete mix achieves a high density and cures over time into a strong monolithic block. Roller-compacted concrete is typically used for concrete pavement, but has also been used to build concrete dams, as the low cement content causes less heat to be generated while curing than typical for conventionally placed massive concrete pours.

Glass concrete

The use of recycled glass as aggregate in concrete has become popular in modern times, with large scale research being carried out at Columbia University in New York. This greatly enhances the aesthetic appeal of the concrete. Recent research findings have shown that concrete made with recycled glass aggregates have shown better long term strength and better thermal insulation due to its better thermal properties of the glass aggregates.

Asphalt concrete

Strictly speaking, asphalt is a form of concrete as well, with bituminous materials replacing cement as the binder.

Rapid strength concrete

This type of concrete is able to develop high resistance within few hours after being manufactured. This feature has advantages such as removing the formwork early and to move forward in the building process at record time, repair road surfaces that become fully operational in just a few hours.

Rubberized concrete

While “rubberized asphalt concrete” is common, rubberized Portland cement concrete (“rubberized PCC”) is still undergoing experimental tests, as of 2007.

Polymer concrete

Polymer concrete is concrete which uses polymers to bind the aggregate. Polymer concrete can gain a lot of strength in a short amount of time. For example, a polymer mix may reach 5000 psi in only four hours. Polymer concrete is generally more expensive than conventional concretes.

Geopolymer or green concrete

Geopolymer concrete is a greener alternative to ordinary Portland cement made from inorganic aluminosilicate (Al-Si) polymer compounds that can utilize 100% recycled industrial waste (e.g. fly ash and slag) as the manufacturing inputs resulting in up to 80% lower carbon dioxide emissions. Greater chemical and thermal resistance, and better mechanical properties, are said to be achieved by the manufacturer at both atmospheric and extreme conditions.

Similar concretes have not only been used in Ancient Rome (Google Roman Concrete) as mentioned but also in the former Soviet Union in the 1950s and 1960s. Buildings in the Ukraine are still standing after 45 years so that this kind of formulation has a sound track record.

Limecrete or lime concrete is concrete where cement is replaced by lime

Refractory Cement

High-temperature applications, such as masonry ovens and the like, generally require the use of a refractory cement; concretes based on Portland cement can be damaged or destroyed by elevated temperatures, but refractory concretes are better able to withstand such conditions.

Concrete Breakout

This is the term used when the location of the pier is obstructed by some form of concrete (i.e. patio or walkway.)

Concrete Slab

Concrete that is typically poured in a single piece and serves as base support for a building. A slab foundation is reinforced with steel rebar and/or steel stressed cables, and other methods. Slab foundations may have footers made of the same materials. Required dimensions and components of slabs and footers may be dependent on local building codes. A concrete slab sits directly on surrounding soil. Also called Slab On Grade.


The change of water from vapor to liquid when warm, moisture-laden air comes in contact with a cold surface. The conversion of a molecule of moisture/vapor that when exposed to something colder, decreases in size and squeezes out the denser liquid. This occurs on the cooler walls and floors and pipes in basements much the same as it does on the outside of a glass of ice water, and is always worse when the relative humidity is highest.


A joint connected by welds or bolts used to transmit forces between two or more members.


The term given to a structural system denoting the transfer of loads and stresses from member to member as if there were no connections.

Continuous Span

A span that extends over several supports and having more than two points.

Continuous Weld

A weld which extends continuously from one end of a joint to the other.


A legal document or agreement, enforceable by law, between two or more parties for the doing of something specified, such as the building of a building or furnishing materials.

Contract Documents

Contract drawings, specifications, etc., used to build a structure which define the responsibilities of the parties involved.

Contract Drawings

All the architectural, structural, mechanical, electrical, etc. plans that make up a legal set of contract documents to build a building by.

Conventional Framing

Framing using conventional joist, beams, columns, masonry walls, etc. instead of framing used in Metal Building construction.

Cool Roofing

A cool roof is defined as a roof surface that has both high reflectivity and high emissivity. High reflectivity requires the surfacing material to reflect solar energy away from the surface. High emissivity requires radiating heat energy away from the surface. Roofs undergo significant expansion and contraction as they heat and cool throughout the day. Heat absorbed by the roof can also accelerate degradation by ultraviolet rays and water. A reflective roof can reduce the amount of thermal shock that occurs on the roof surface and prolong the life of the roof. The covering piece on top of a wall, conventionally covered with metal. A more modern and effective


The process of removing certain sections of a structural steel member to allow easier fitup to the supporting structural member.


Successive courses of masonry projecting from the face of a wall to increase its thickness or to form a shelf or ledge for a structural member to bear on.

Counter flashing

That portion of the flashing attached to a vertical surface to prevent water from migrating behind the base flashing.


A row of shingles or roll roofing running the length of the roof.

Cove/Wall Cove

The joint where the wall and the floor meet. This is a common area for water intrusion in a basement.

Cover Plate

A long plate usually welded to the top or bottom flange of a rolled steel beam or to the bottom chord of a joist or joist girder to increase the load carrying capacity of that member.


Amount of weather protection provided by the roofing material. Depends on number of layers of material between the exposed surface of the roofing and the deck; i.e., single coverage, double coverage, etc. Usually expressed in gallons per square foot.

The width of a deck sheet, i.e., 30 inches or 36 inches.

Cracked Walls or Floors

Cracks can form in walls and floors for a number of reasons from settlement, expansion and contraction, water pressure and even by design. The crack is not the problem it is only the symptom. Water entering through the crack is a problem and only enters when there is enough pressure to force it to penetrate the opening. Eliminate the pressure and eliminate the water. (See Crack Repair)


1) A machine used to move material by means of a hoist. 2) A machine that can usually move and is used to lift heavy materials or to lift members that are to be erected in a structure.

Crawl Space – A shallow unfinished space beneath the first floor or under the roof usually for access to plumbing, heating ducts and wiring. Crawl spaces should have adequate ventilation to reduce the effects of condensation and to expel stagnant air. Water pipes should be wrapped especially in unheated spaces. (See Crawl Space Waterproofing)


A time-dependent deformation of a structural member under a sustained constant load. An unpopular person.


A ridge or drainage diverting roof framing.

Crimped Angle Web

A regular angel whose ends have been ‘crimped’ in the shape of a ‘U’ whose out-to-out distance is usually one inch. The actual crimped portion of the angle is only a few inches on each end and the end is inserted between top or bottom chord members to be welded.

Critical Load

The load at which deflection of a member or structure occurs as determined by stability analysis.

CSI (Construction Specifications Institute)

Abbreviation. (Unrealistic and Overrated TV Show 🙂


A raised edge of a concrete floor slab or support for a mechanical unit.

Cured Concrete

concrete that has attained its intended design performance properties.


The hardening of concrete, epoxy, resin or other materials; The process of protecting masonry against loses of moisture during the early stages of setting.

Curtain Wall

A non-load bearing exterior wall which carries only its own weight and wind load.


The rotation per unit length of a member due to bending forces.

Cut And Fill

Removal of excess existing soil (cut) to low or deficient areas (fill) for contouring purposes.


A list of components with dimensions used for fabrication and accounting purposes.



For floor vibrations, it is the rate of decay of amplitude.


Liquid diffused or condensed in a relatively small quantity on the walls or floor. The effects of moisture created from capillary action or condensation and can often be controlled by heating the space, having adequate ventilation, by using a properly sized dehumidifier or a combination of all the afore mentioned remedies.


An application or system that is installed when the house is built to resist water vapor or minor amounts of moisture and acts as a backup to primary waterproofing systems. Dampproofing materials are subject to the effects of weathering and deterioration and are not effective against water pressure. This is most often a spray, brush or rolled on type sealer that will repel water but will not span any type of shrinkage crack or structural separation.


A large float of metal or wood, used to smooth freshly poured concrete.

Daylight Drains

Refers to the end of the foundation drain pipe which runs to daylight or gravity feed. There must be sufficient slope or grade. This is the end result of installing the foundation drain, and placing the end of the foundation drain tiles so they run to daylight to function properly. The foundation pipe must be routed with the proper fall (slope) to a point where it is naturally running to open(daylight). This daylight condition can also be achieved if the drains are routed to a catch basin or storm sewer that in turn is sloped in such a way as to allow any water that finds its way in to be discharged.

Dead Load

Loads due to the weight of the components making up the structure and that are intended to remain permanently in place.


A floor or roof covering made out of gage metal attached by welding or mechanical means to joists, beams, purlins, or other structural members and can be galvanized, painted, or unpainted.

Deck or Decking

The structural “skin” of a roof over which roofing in applied. Most new homes have decking made of plywood. There are four main types of decking commonly used on residential roofing projects

  • Plywood: Plywood is strong, durable, and light. It comes in many grades with ratings from A to D. Use only exterior grade plywood for decking. The thickness of plywood depends on the spacing of the rafters.
  • OSB: Oriented strand board (OSB) is cheaper than plywood, but not as strong as plywood, and does not hold nails as well as plywood. One side has a slip resistant coating and should be placed facing up.
  • Tongue and groove 2-by-6: If a roof will be seen from the inside (no ceiling installed), tongue and groove is used. It is a wood decking that provides great insulation without additional rigid roof insulation in moderate climates. Also, the boards can be painted or stained on the inside to match the interior.
  • Step sheathing: Step sheathing is used alone or in combinations with solid sheathing for installation of tiles or shakes. Step sheathing allows air circulations under the tiles by using 1-by-6 or 2-by-6 boards that are evenly spaced so that air can move under the tiles or shakes.

Deck Type

The specific type of deck to be specified, such as Type “B” Wide Rib, Type “F” Intermediate, Type “N” Deep Rib, Type “A” Narrow Rib, Composite, Cellular, etc.

Deep Foundation

A design whereby structural load is transmitted to a soil at some depth, usually through piers, piles, or caissons. (See Understanding Residential Construction)


The displacement of a structural member or system under load.


The act of distorting or changing the shape or dimensions of a structural element or body resulting from forces or stresses.

Degree Days

The difference between a reference temperature (usually 65° F, 18.3° C) and the mean temperature for the day, times 24 hours, times the number of days in the period. Degree days are used to compare the severity of cold or heat during the heating or cooling season.


A dehumidifier is a household appliance that reduces the level of humidity in the air, usually for health reasons, as humid air can cause mold and mildew to grow inside homes, which has various health risks. Relative humidity is preferably 30 to 50%. An appliance that condenses air molecules using cold temperatures which in turn “squeezes” the moisture out of the molecule into a tray which must be emptied when full. It is best to have the unit sized for your particular needs by a qualified representative at the local hardware or building supply store as an under-sized unit is of little value.

Equipment designed to reduce the amount of water vapor in the atmosphere. There are three methods by which water vapor may be removed: (1) the use of sorbent materials, (2) cooling to the required dew point, and (3) compression with aftercooling.

Sorbents are materials which are hygroscopic to water vapor. Solid sorbents include silica gels, activated alumina, and aluminum bauxite. Liquid sorbents include halogen salts such as lithium chloride, lithium bromide, and calcium chloride, and organic liquids such as ethylene, diethylene, and triethylene glycols and glycol derivatives.

Solid sorbents may be used in static or dynamic dehumidifiers. Bags of solid sorbent materials within packages of machine tools, electronic equipment, and other valuable materials subject to moisture damage constitute static dehumidifiers. A dynamic dehumidifier for solid sorbent consists of a main circulating fan, one or more beds of sorbent material, reactivation air fan, heater, mechanism to change from dehumidifying to reactivation, and aftercooler.

The liquid-sorbent dehumidifier consists of a main circulating fan, sorbent-air contactor, sorbent pump, and reactivator including contactor, fan, heater, and cooler. This unit will control the effluent dew point at a constant level because dehumidification and reactivation are continuous operations with a small part of the sorbent constantly bled off from the main circulating system and reactivated to the concentration required for the desired effluent dew point.

A system employing the use of cooling for dehumidifying consists of a circulating fan and cooling coil. The cooling coil may use cold water obtained from wells or a refrigeration plant, or may be a direct-expansion refrigeration coil. In place of a coil, a spray washer may be used in which the air passes through two or more banks of sprays of cold water or brine, depending upon the dew-point temperature required.

Dehumidifying by compression and aftercooling is used when the reduction of water vapor in a compressed-air system is required. This is particularly important, for example, if the air is used for automatic control instruments or cleaning of delicate machined parts. The power required for compression systems is so high compared to power requirements for dehumidifying by either the sorbent or refrigeration method that the compression system is not an economical one if dehumidifying is the only end result required.

A desiccant dehumidifier is a device that employs a desiccant material to produce a dehumidification effect. As they are more effective for low-temperature and low (relative) humidity levels, they are generally used for these conditions instead of mechanical/refrigerative dehumidifiers – or are used in tandem with them.


Separation of the laminated layers of a component or system.


Separation of stone layers along its bedding planes.


A series of Small Square toothed or block like projections, which are usually found below a piece of molding. Most commonly associated with Greek revival and Colonial Revival structures.


Roadside crosses; often found on alongside sharp bends in roadways.

Depth of Joist

The out-to-out distance from the top of the top chord to the bottom of the bottom chord taken a some reference location, usually at the midspan of the joist or joist girder.

Design Documents

The plans, details, sections, specifications, etc. prepared by the building designer.

Design Length

The ‘span’ of a joist or joist girder in feet minus 0.3333 feet.

Design Loads

The loads specified in the contract drawings or specifications which a building is to be designed for.

Design Strength

The resistance provided by a structure, member, or connection to the forces imposed on it.


The state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic substance that induces or sustains such a state in its local vicinity in a moderately-well sealed container. (hydrology) The permanent decrease or disappearance of water from a region, caused by a decrease of rainfall, a failure to maintain irrigation, or deforestation or overcropping. (science and technology) Thorough removal of water from a substance, often with the use of a desiccant.

Diagonal Bracing

Structural members which are inclined and are usually carrying axial load which enable a structural frame to behave as a truss to resist horizontal loads.

Diagonal Bridging

Two angles or other structural shapes connected from the top chord of one joist to the bottom chord of the next joist to form an ‘X’ shape whose l/r ratio cannot exceed 200. The bridging members are almost always connected at their point of intersection.


Roof panel or decking, metal wall, or floor slab which provides a larger in-plane shear stiffness and strength adequate to transmit horizontal forces to the resisting structural system.

Diaphragm Action

The resistance to a racking affect or in-plane shear forces offered by roof deck, panels, or other structural members when properly attached to a structural frame.

Differential Moisture Content

A frequent source of foundation damage is the differential expansion of soil under and near the foundation. Moist soil is adjacent to dry soil. Differential Moisture Content can be caused by low areas that hold water longer than surrounding areas, watering of lawns and garden beds, absence of gutters which direct water away from the foundation, water leaks, etc.

Differential Settlement

Differential settlement is when one part of a foundation settles more than another part. A footing crack in one part of the foundation would be considered differential settlement. This can cause problems to the structure the foundation is bearing or supporting. It is necessary that a foundation is not loaded beyond its bearing capacity or the foundation will “fail.” Total settlement is when the entire structure settles. (See Understanding Residential Construction)

Dimensional shingle

A shingle that is textured, overlayed, or laminated and designed to produce a three-dimensional effect. Similar to Laminated shingle and Architectural shingle.

Discharge Line

The pipe used to direct the water away often from a sump pump. Discharge lines should be checked periodically to insure there are no obstructions that might restrict the water flow. Long discharge lines will freeze under the right conditions and should be kept as short as possible in northern climates.

Dissolution of Marble

Very advanced stage of deterioration; a combination of multiple decay mechanisms including, erosion, sugaring, and spalling.


Geologically it is a name for a carbonate rock that consists dominantly of this compound. As a mineral component, it is found it certain crystalline schist’s, and in beds of gypsum.

Dolomitic Limestone

Limestone containing 10% – 80%, mineral dolomite.


The simplest, and most basic of the three Greek orders, (Doric, Ionic, Corinthian). It is associated with thick columns, and a capital with a flat bowl below a block. The column does not stand on a base.


A framed window unit that projects through the sloping plane of a roof.

Double coverage

Application of asphalt roofing such that the lapped portion is at least two inches wider than the exposed portion, resulting in two layers of roofing material over the deck.

Double Curvature

When end moments on a structural member produce a bending effect which cause the member to form an S shape or has a reversal in curvature.


A pipe for draining water from roof gutters. A downspout is also called a leader.The pipe from the roof gutter system that, in conjunction with the leaders, directs the roof water away from the foundation.

Downspout Extensions

Solid pipe that extends from the end of a downspout, usually 6-10 feet from the foundation wall, to keep excessive water from the foundation. Always recommended!

Downstanding Leg

The leg of a structural angle which is projecting down from you when viewing.

Drainage Correction

A system in which the foundation is protected against excessive water damage. Depending upon the grade of the land at and around the foundation, a French drain or swale would be used to direct run-off.

  • Ponding water can promote extreme foundation settlement when the soil stays excessively wet.
  • Flooding or rushing water can cause serious damage by erosion of soil at/or under the structure.

Drain Media

This comes in a variety of styles. It can be a fiberglass type board, extruded insulation board with grooves in it or a ‘dimple’ board, this looks similar to an egg crate configuration. Perhaps the most effective drain media is washed stone. It is generally used on top of the drain pipe or foundation drain only. It is cost prohibitive to use it all the way up the foundation wall as a drain media.

Drain Pipe

Modern term for drain tile. Drain pipe comes in a variety of shapes and sizes, solid and perforated. Used for drainage of soils, foundations, septic systems, and a host of other applications.

Drain Tile

Drain Pipe. Previously made of terra cotta (clay) and other hard materials laid end-to-end, drain tile is now commonly made of flexible, perforated polyethylene tubing and is laid near the footing level to aid in the control of below grade water problems.


To shape a stone finely to fit in place.

Dressed Stone

The stone in masonry, after it has been squared with a hammer and chisel.


The lateral movement or deflection of a structure.

Drift Index

The ratio of the lateral deflection to the height of the building.

Drift Pin

A tapered pin used during the erection process to align holes in steel members which are to be connected by bolting.

Drilled Pier

Until the early 90’s, this was the main method used to support a failing foundation. The method of installation is A) Drill a hole, at an angle, to a pre-determined depth under the slab – usually no more than 10 feet down. C) Form in rebar into the hole and form an 18″ cap on top. C) Fill the hole with concrete after mixing with a curing agent and let the concrete set-up for 7-14 days. KEY POINTS This pier will carry a 3-10 year warranty on average with a charge to make adjustments up to 100% of the cost of the pier. Since this pier is only drilled to a predetermined depth and at an angle, it’s expected to fail in that time frame if the things that caused the foundation to fail in the first place are not addressed. The soil that is drilled out of the ground will be piled up around the home for the 7-14 days which will cause the foliage in that area to die in most cases.

Drip Edge

a metal flashing or other overhanging component, with an outward projecting lower edge, intended to control the direction of dripping water and help protect underlying building components. A drip edge also can be used to break the continuity of contact between the roof perimeter and wall components to help prevent capillary action.


Any tube, pipe or other conduit by which air or fluid is transferred.

Duct Opening

The round or square opening required through the web system of a joist or joist girder to allow passage of a duct.


Is the ability of a material to withstand large inelastic deformations without fracture. Structural steel has considerable ductility.

Ductility Factor

The ratio of the total deformation at maximum load to the elastic-limit deformation.

Dynamic Load

A load that varies with time which includes repeative loads, seismic loads, and other loads created by rapid movement.

Dry In

To make a building waterproof.

DRYLOK® / Dry Lok / Dryloc

A brand name waterproof paint used by DIY’ers to waterproof basement walls or masonry walls. Latex or oil based. This is a product we have seen endorsed by many home improvement ‘guru’s who seem to know everything but waterproofing. Instead of waterproofing the walls, what dry loc does is seal the moisture in the wall, seals the acid-rich water in the concrete block. This, in turn, accelerates the corrosive process, destroying the block, as opposed to fixing the moisture problem in the first place. In our many inspections, over 10,000 to date, we’ve seen our fair share of DRYLOK® and in most cases, the material caused damage in every situation. Not one situation exists where we encountered this product solving any waterproofing issues or problems. A poor analogy is ‘cover your eyes’ – now the problem is no longer visible – again, the reality is, although you can no longer see the problem, it is now getting worse at an accelerated speed. Better to do nothing, than use this product. Our opinion. Be Safe, Be Sure! Call Foundation Expert Waterproofing.


Stonework with mortar recessed so that it is invisible.

Dry Stone Wall

A stone wall built without mortar.

If you have questions please call (877) 344-1155 or email sam@theFoundationExpert.com



Earth Anchor

A steel shaft containing one or more helixes which is screwed into the earth to provide a retention system against uplift forces.


The horizontal, lower edge of a sloped roof. The line along the sidewall of a building formed by the intersection of the plane of the roof and the plane of the wall.

Eave Height

The vertical distance from finished floor to the eave.

Eave Strut

A structural member located at the eave of a building which supports a roof and/or wall panels.


The condition that exists when a load is applied on a line of action that does not pass through the centroid of the body it is applied to.


The distance between a line of action of force and the centroid of the member it is applied to.

Edge Angle

A structural angle that is connected around the edge of a joist extension or other member. An angle used around the sides of a floor to contain the concrete when it is being poured which is also called a Pour Stop.

Edge Distance

The distance from the center of a hole to the edge of a connected part.

Edge Strip

The width or region around the edges of a building where uplift values are higher than in the interior of the roof.

Effective Depth

The distance from the centroid of the top chord to the centroid of the bottom chord.

Effective Length

The equivalent length, KL, used in compression formulas. This method estimates the interaction effects of the total frame on a compression member by using K factors to equate the strength of a framed compression member of length L to an equivalent pin-ended member of length KL subject to axial load only.

Effective Length Factor (K)

The ratio between the effective length and the unbraced length of a member measured between center of gravities of the bracing members. K values are given for several idealized conditions in which joint rotation and translation are realized.

Effective Moment of Inertia

The moment of inertia of the cross section of a member that remains elastic when partial plastification takes place.

Effective Width

The transverse distance indicating the amount of slab that acts in conjunction with the supporting member.


The staining and discoloring of masonry walls and floors as a result of water-carried acids and chemicals. Often confused with mildew in appearance. An encrustation of soluble salts, commonly white, deposited on the surface of stone, brick, plaster, or mortar; usually caused by free alkalis leached from mortar or adjacent concrete as moisture moves through it. In chemistry, Efflorescence is the loss of water (or a solvent) of crystallization from a hydrated or solvated salt to the atmosphere on exposure to air.

Primary efflorescence

Primary efflorescence is named such, as it typically occurs during the initial cure of a cementitious product. It routinely occurs in masonry construction, particularly brick, as well as some firestop mortars, when water moving through a wall or other structure, or water being driven out as a result of the heat of hydration as cement stone is being formed, brings salts to the surface that are not commonly bound as part of the cement stone. As the water evaporates, it leaves the salt behind, which forms a white, fluffy deposit, that can normally be brushed off. The resulting white deposits are referred to as “efflorescence” in this instance. In this context efflorescence is sometimes referred to as “saltpetering.” Since primary efflorescence brings out salts that are not ordinarily part of the cement stone, it is not a structural, but, rather, an aesthetic concern.

For controlling primary efflorescence, formulations containing liquid fatty acid mixtures (e.g., oleic acid and linoleic acid) have been commonly used. The oily liquid admixture is introduced into the batch mix at an early stage by coating onto the sand particles prior to the introduction of any mix water, so that the oily admixture is distributed uniformly throughout the concrete batch mix.

Secondary efflorescence

Secondary efflorescence is named such as it does not occur as a result of the forming of the cement stone or its accompanying hydration products. Rather, it is usually due to the external influence of concrete poisons, such as chlorides. A very common example of where secondary efflorescence occurs is steel-reinforced concrete bridges as well as parking garages. Saline solutions are formed due to the presence of road salt in the winter. This saline solution is absorbed into the concrete, where it can begin to dissolve cement stone, which is of primary structural importance. Virtual stalactites can be formed in some cases as a result of dissolved cement stone, hanging off cracks in concrete structures. Where this process has taken hold, the structural integrity of a concrete element is at risk. This is a common traffic infrastructure and building maintenance concern. Secondary efflorescence is akin to osteoporosis of the concrete.

For controlling secondary efflorescence, admixtures containing aqueous-based calcium stearate dispersion (CSD) are often added at a later stage of the batching process with the mix water. In a typical batching process, sand is first charged into the mixer, then the oil-based primary anti-efflorescence admixture is added with constant mixing to allow the oil to coat the sand. Then coarse aggregates, colorants, and cement are added, followed by water. If CSD is used, it is then introduced usually at this point during or after the addition of the mix water. CSD is an aqueous dispersion wherein fine solid particles of calcium stearate are suspended in the water uniformly. Commercially available CSD has an average particle size of about 1 to 10 microns. The uniform distribution of CSD in the mix may render the resulting CMU water repellent, as CSD particles are well distributed in the pores of the unit to interfere with the capillary movement of water.

Protecting against efflorescence

It is possible to protect porous building materials such as brick, tiles, concrete and paving against efflorescence by treating the material with an impregnating, hydro-phobic sealer. This is a sealer which repels water and will penetrate deeply enough into the material to keep water and dissolved salts well away from the surface. However, in climates where freezing is a concern, such a sealer may lead to damage from freeze/thaw cycles.

Efflorescence can often be removed using phosphoric acid. After application the acid dilution is neutralized with mild diluted detergent, and then well rinsed with water. However, if the source of the water penetration is not addressed efflorescence may reappear.

Common rebar protective measures include the use of epoxy coating as well as the use of a slight electrical charge, both of which prevent rusting. One may also use stainless steel rebar. Certain cement types are more resistant to chlorides than others. The choice of cement, therefore, can have a large effect upon the concrete’s reaction to chlorides.


Exterior Insulating Finish System; exterior wall cladding system consisting primarily of polystyrene foam board with a textured acrylic finish that resembles plaster or stucco.


Abbreviation for ‘Expansion Joint’.

Elastic Analysis

The analysis of a member which assumes that material deformation disappears on removal of the force that produced it and the material returns to its original state.


“Elast” from “Elastic” and “omer” from “Polymer”. A natural or synthetic material which, at room temperature, can be stretched under low stress and, upon immediate release of the stress or force, will return quickly to its approximate original dimensions.


The elastic, rubber-like properties of a material that will stretch when pulled and will return relatively quickly to its original shape when released.


The device through which current is conducted thru to the arc or base metal during the process of welding.


Measurements that determine the difference in height between the central point, of a building and other reference points. Elevation is a series of measurements to determine the difference in height between a central point and other points.


Measurements taken by instruments (usually optical) to establish grades.


The ability of a material (e.g., roofing membrane) to be stretched by the application of a force.


A steel member such as a plate, bolt, stud, or bar cast into a concrete structure which is used to transmit applied loads to the concrete.


To add ornament so as to adorn. To add decorative elements.


A grayish black mineral used as an abrasive; example, emery cloth which is a type of fine sand paper.


The measure of a surface’s ability to emit long-wave infrared radiation.


Based on practical experience.

End Bay

The bay which is located from the end of a building to the first interior main frame.

End Diagonal or Web

The first web member on either end of a joist or joist girder which begins at the top chord at the seat and ends at the first bottom chord panel point.

End Distance

The horizontal distance from the first top chord panel point at the end of a joist to the first bottom chord panel point.

End Lap

The lap at the end of a sheet of deck which bears over the primary support (joist or beam).

End Moment

A moment which is generated at one end or both ends of a joist, joist girder, or beam due to continuous frame action which can be caused by wind, live load, or dead load moment.

End Panel

The distance from the panel point at the joist seat to the first top chord panel point towards the interior.

End Wall

An exterior wall which is perpendicular to the ridge of the building.

Energy Star®

A registered trademark of the U.S. government. The ENERGY STAR® Program* represents a voluntary partnership between the federal government and businesses to promote energy efficiency and environmental activities. ENERGY STAR® labeled roof products are reflective and lower roof surface temperature by up to 100°F., decreasing the amount of heat transferred into a building. ENERGY STAR® labeled roof products are designed to help save money on utility bills and reduce energy waste. Reflective roof products can help reduce the “heat island effect,” a phenomenon in which cities can be 2 to 8°F. warmer than the surrounding countryside. Such heat islands occur, in large part, because many buildings and paved surfaces are designed with dark materials that absorb heat from the sun. This heat is released at night, causing the air temperature to remain high. The resulting elevated temperature leads to an increased demand for air conditioning in buildings, increased fuel use for vehicle air conditioning, increased levels of smog, and associated increased levels of heat-related and smog-related health problems. Installing reflective roofs helps reduce the heat island effect, decreasing the amount of smog in the air and benefiting the entire community. *ENERGY STAR® is a registered trademark of the U.S. government.

Engineer’s Report

When a home is repaired, a 3rd party Engineering Report should be ordered to assure you that the plan of repair set into place is accurate and will correct the foundation problems adequately.


Inscription formed by carving or sandblasting into stone.


The Greek revival style, the horizontal group composed of three members, held up by the columns. From the lowest to highest in a structure the three members include; architrave, frieze, and the cornice.


A graphical plot indicating the maximum magnitude of an internal force effect such as flexual stress, shear stress, axial stress, torsional stress, etc. due to a series of load combinations.


Abbreviation for ‘Edge of Deck’.


Abbreviation for ‘Edge of Joist’.


Abbreviation for ‘Edge of Slab’.

Equations of Equilibrium

The equations relating a state of static equilibrium of a member or structure when the resultant of all forces and moments are equal to zero. Three equations must be fulfilled simultaneously Sum of the forces in the X-direction must equal zero, sum of the forces in the Y-direction must equal zero, and the sum of the moments about any point must equal zero for a two dimensional structure.

Equivalent Uniform Load

A uniform load (in plf) derived from the maximum reaction (in lbs) or the maximum moment (in inch-lbs) of a member carrying various loads.

Formula Weq= 2 * max. reaction (in lbs) divided by length (in feet) or Weq=(8 * max. moment) divided by (lenght^2 (in feet) * 12)


The process of installing joists, joist girders, beams, bridging, deck, or other structural members in order to construct a structure.

Erection Plan

Floor or roof plans that identify individual marks, components, and accessories furnished by the joist manufactures in a detailed manner to permit proper erection of the joist and joist girders.


The person or company that actually does the erecting of the joist or joist girders for a job.


When pertaining to stone; gradually wearing away of surface; associated with sugaring in marble. Regarding landscape, the slow tendency of earth to move down hill, through the forces of wind water, and ice.


To change into or pass off in vapor; Important part of the rising damp cycle in gravestones; the force which pulls salts and minerals towards the surface of stone and masonry structures combined with capillary action.


The process of digging out or around something.


Excavation of , digging out around the foundation of a building. The removal of earth from its natural position.

The cavity resulting from the removal of earth.


Peeing or scaling of stones surface.

Expansion Joint

A structural separation between two building elements that allows free movement between the elements without damage to the roofing or waterproofing system. A break in construction or a special design detail to allow for thermal expansion and contraction of the materials of a structure.


Portion of the shingle exposed to the weather. Exposure is measured from the butt of one shingle to the butt of the next.

Extensive (Green Roof)

A Green Roof with plantings such as grasses or small plants.

Extended End

The extended part of a joist top chord with also the seat angles extended from the end of the joist extension back into the joist maintaining the standard 2 1/2 inch end bearing depth over the entire length of the extension.

Exterior waterproofing

Exterior waterproofing prevents water from entering foundation walls therefore preventing the wicking and molding of building materials. Waterproofing a structure from the exterior is the only method the IBC (International Building Code) recognizes as adequate to prevent structural damage caused by water intrusion. Prior to the 1980’s much of the original exterior waterproofing was actually damp-proofing using a degradable asphalt-based covering. Today, however, Polymer products such as Tremco’s Paraseal membrane will completely waterproof an exterior foundation wall. This material has a half life in the thousands of years which makes it ideal for a long term exterior waterproofing solution. Asphalt and tar based compounds are affected by soil pH and break down after 10-20 years, thus making that type of waterproofing ineffective over time.



A woven cloth or material of organic or inorganic filaments, threads or yarns used for reinforcement in certain membranes and flashings. Factory Mutual Research Corporation (FMRC) (commonly referred to as “FM”) a research and testing organization that classifies roofing components and assemblies for their fire, traffic, impact (hail), weathering, and wind-uplift resistance for four major insurance companies in the United States. Their specifications have become industry standards.


The manufacturing process to convert raw materials into a finished product by cutting, punching, welding, cleaning, and painting.

Factor of Safety

Is the ratio of the ultimate load for a member divided by the allowable load for a member and must always be greater than unity.

Factored Load

The product of the nominal load and a load factor.


For joists and joist girders, when looking at the member with the tagged end to the right, it is the side that is opposite the side you see first.


The flat surface located at the outer end of a roof overhang or cantilever end or also a decorative trim or panel which projects from the face of a wall. Horizontal trim at the eaves that covers the rafter ends.


Any of a wide variety of mechanical devices and assemblies, including nails, screws, cleats, clips, and bolts, which may be used to secure various components of a roof assembly. Term for a connecting device such as a weld, bolt, rivet, etc.


Cement brought to the surface by floating the slab.

Fat Mortar

A very sticky mortar due to lack of sand.


Abbreviation for ‘Field Cut’.


Metal spacer used with wedges in drilled holes to crack apart stone.


One of the crystalline minerals in granite.


A flexible sheet that is saturated with asphalt and used as an underlayment, sometimes called “tar paper”.


Refers to objects made of or partially made of iron, such as ferrous pipe.

Ferrous Pinning

Metal that rusts and expands was use extensively in historic monumental installations. It has contributed to a host of problems, including, cracking, staining, stone degradation, and complete collapse in some instances.


A roofing material that has cellulose (wood fiber) mixed into it. Cellulose absorbs water and can add greatly to the roof’s weight, while reducing its longevity.

Fiberglass Insulation

Blanket or rigid board insulation, composed of glass fibers bound together with a binder, faced or unfaced, used to insulate roofs and walls. Rigid boards usually have an asphalt and Kraft paper facer.

Fiberglass Mat

An asphalt roofing base material made from glass fibers.


A term used for the jobsite or building site where construction of the project will take place.


Rough uncut stones as they are picked from a field.

Field Weld

The specific term used for the welding of structural members out at the actual jobsite and not in a fabricators shop.


Soil added to provide a level construction surface or desired grade.


A rod, plate, or angle welded between a two angle web member or between a top or bottom chord panel to tie them together usually located at the middle of the member.

Filter Fabric / Soil Filter

Geotextile. Woven or nonwoven fabrics used with foundations, soils, rock, earth, or other geotechnical material as an integral part of a manufactured project, structure, or system. Also known as civil engineering fabrics; erosion control cloth; filter fabrics; support membrane. Many waterproofers and engineers recommend or use filter fabrics to wrap drain pipe. Filters clog – all fabric filters will eventually clog. If you place a pipe next to clay or silt, the filter fabric will clog faster. If you place the drain pipe, wrapped in filter fabric with washed sand as a secondary filter, the filter will take much longer to clog. A manufacturer states, “15 years.” Without the sand, 3-5 years. Washed sand and gravel act as a better filter, as long as the bridge factor is there. Meaning, the particle size of the gravel and sand is larger than the perforations or slits in the drain pipe.


In deck terminology, the coating on the deck sheet, i.e., galvanized, painted, or unpainted.

Finish Strip

A roof deck accessory made out of gage metal for finishing out runs of deck for small areas of coverage where full sheet coverage is impractical.

Fire Proofing

The process of coating a structural steel member with a fire retardant material to make the member resistant to fire.


The ability of a joist or other structural member to resist a fire due to the type of protection it has, such as membrane protection or spray on protection. There are hundreds of floor-ceiling or roof-ceiling assemblies with their fire-resistance rating given in the Underwriters Laboratory Fire Directory.

Fire Resistance

The ability of a roof top material to act as a barrier to the spread of fire and confine it to the area of origin. There are established test procedures for external fire exposure to classify roof systems into three classes Class A, B, or C.


A half-cylindrical or half-conical shaped opening or void in a lapped edge or seam, usually caused by wrinkling or shifting of plysheets during installation.

Fixed-End Support

A condition where no rotation or horizontal or vertical movement can occur at that end. This type of support has no degrees of freedom. Three reactive forces exist at the rigidly fixed end.


Detachment of a uniform layer of a coating or surface material, usually related to internal movement, lack of adhesion or passage of moisture. Minor delimitation of surface, a form of spalling; Followed by blistering, and scaling, in a successive order of severity.

Flame Spread

Per ASTM E 84, a measure of relative combustibility. The flame spread of a tested material is rated relative to asbestos cement board (flame spread=0) and red oak flooring (flame spread = 100).


The projecting edge of a structural member.

Flange Brace

A structural bracing member used to provide lateral support to the flange of a beam, the bottom chord or a joist girder, or a column.

Flash Point

The critical temperature at which a material will ignite.


Pieces of metal or roll roofing used to prevent seepage of water into a building around any intersection or projection in a roof such as vent pipes, chimneys, adjoining walls, dormers and valleys. Galvanized metal flashing should be minimum 26-gauge. There are 4 main types of flashing used in residential roofing systems

Valley flashing

This flashing is used in open valleys of the roof. Most often leaks are found in the valley flashings due to flashing that is nailed to tightly to the decking or shingles that are not trimmed far enough off the flashing.

Plumbing vent flashing

Plumbing vent flashing prevents rainwater from running into holes cut for pipes in the roof. This flashing is sold according to the size of the vent pipe and the roof angle. Roofing material is installed over the flashing.

Lead flashing

When working with tile roofs, lead flashing is used. In the case of a plumbing vent flashing, the lead flashing is actually molded to the shape of the tile’s surface. Then the top of the lead flashing is covered by the next tile to prevent water from seeping under the flashing.

Step flashing

When a chimney or dormer wall intercepts the slope of the roof, step flashing is used. Step flashing is usually a metal piece that is bent in the middle, so that one end lays on the roof, and the other against the vertical wall of the dormer or chimney.

Flashing is one of the most important elements of the roof because it seals the seams and joints of the roof–the locations where leaks are most likely to occur. Often, flashing is not maintained well, or installed correctly in the first place. Check for the following signs that your flashing needs maintenance or repair

  • Rusting of metal flashing
  • Excess leaves and debris in valleys or seams of the roof (can lead to rusting and corroding of the metal)
  • Prolonged exposure to the elements such as moisture, UV rays, climate changes–especially when asphalt compounds or caulking material is used. Look for cracks, loss of elasticity and delamination.

In many cases the flashing can be cleaned and then repaired, relaminated or repainted (even in the case of rust). In other cases, the flashing may need to be replaced.

Flashing cement

An asphalt-based cement used to bond roofing materials. Flashing cement is also known as mastic.

Float– A wooded tool used to finish a concrete or masonry surface.

Fluid-Applied Elastomer

A liquid Elastomeric material that cures after application to form a continuous waterproofing membrane.


Optical effect whereby a mineral appears a different color in ultraviolet light then in ordinary daylight.


A groove or channel cut or carved in as an architectural decoration. Most commonly placed as parallel grooves, as found on an Ionic column. The fold or bend in a sheet of deck which forms a groove or furrow.

FMS (Factory Mutual System)

A leader in property loss prevention engineering and adjustment. It helps companies prevent and control property loss through research, engineering, and education.

Folding Partition

A moveable wall on a track suspended from a joist or beam which usually folds like an accordion and can be stored in a closet or pocket in a wall.


Patterns caused by aligned crystals in metamorphic rocks.


Used to shape concrete, as in the construction of a replacement base, to reset a broken tablet stone.

Footing / Footer (See Understanding Residential Construction)

Concrete poured into a form below the frost line and above the normal water table and allowed to cure. This then becomes the base upon which the walls are built and helps to distribute the load. A footing is a lower level pier support which is used to support non-load bearing areas like patio’s, porches or small enclosed additions. They are less expensive on average and will not cause structural damage when being placed under such small areas that do not have a thick beam. Some structures used footings during original construction to gain depth into the soil. An object, usually part of a concrete slab, that provides support for the building’s foundation Footers help distribute the weight of the foundation and building evenly throughout the entire foundation.


Temporary structure, usually made of wood, metal, Styrofoam, built to hold concrete during the pour and initial hardening. A temporary construction to contain wet concrete in the required shape while it is cast and setting.

Foundation (See Understanding Residential Construction)

A home foundation is that part of the structure that is in direct contact with the ground. The foundation transmits the weight of the entire home and itself to the supporting soil.

A foundation is a structure that transfers loads to the earth. The structure of something is how the parts of it relate to each other, how it was built. The age of your home can sometimes determine how your home was built and whether it even had a foundation to begin with. Is it 200 years old? Then it most certainly was built with stone, as opposed to more modern types of building materials such as terra cotta block in the late 1800’s to early 1900’s; cinder block, then concrete block, brick, pre-cast or cast-in-place (poured) cement, etc.; and, we find many homes which are 80–200 years old which were built without a footing or foundation upon which the walls rest. That determination is sometimes easy to make, sometimes only when the floor is opened up.

Foundations are designed to have an adequate load capacity with limited settlement – this is usually determined by a geotechnical engineer; the foundation itself is designed structurally by a structural engineer. The primary design concerns are settlement and load bearing capacity. When we consider settlement, we have total settlement, the entire structure settling as one total unit, and differential settlement. Differential settlement is when one part of a foundation settles more than another part. A footing crack in one part of the foundation would be considered differential settlement. This can cause problems to the structure the foundation is bearing or supporting. It is necessary that a foundation is not loaded beyond its bearing capacity or the foundation will “fail.”

Other design considerations, especially in the MD / VA / DC geographical area, include scour and frost heave. Scour is when flowing water removes supporting soil from around a foundation, which may cause undermining and footing cracks. Frost heave occurs when water in the ground freezes to form ice lenses, which may cause footing and wall cracks. Frost action and heaving is a phenomenon that occurs in the winter and early springtime in Northern and Northeastern climates. Essentially, all surface soils undergo some frost action, the magnitude of which is dependent upon the climate and precipitation found in that geographic location.

Foundation Drains

These drains are located at the bottom of the foundation walls whether it is a basement or a crawl space foundation. The drain may be on the footing, against some type of drain media or on the side of the footing, either way is correct if installed properly. Some of the newer waterproofing systems require the foundation drain to be on the footing, in contact with the drain media

Foundation Ties

Metal or plastic wires that hold the foundation panels and rebar in place while concrete is being poured.

Foundation Types (See Understanding Residential Construction)

In general, foundation engineering applies the knowledge of geology, soil mechanics, rock mechanics, concrete, steel and structural engineering to the design and construction of foundations for building and other structures. The most basic aspect of foundation engineering deals with the selection of the type of foundation, such as using a shallow or deep foundation system. Foundations are commonly divided into two categories: shallow and deep foundations.

Deep foundations, usually designed for commercial buildings, which have multiple stories, are used to transfer a load from a structure through an upper weak layer of soil down to a stronger deeper layer of soil such as bedrock. There are varieties of deep foundations including caissons, piers, piles, drilled shafts, and earth stabilized columns. The naming conventions for different types of foundations vary between different engineers. (We will only concern ourselves with shallow foundations, as this is ‘Understanding Residential Construction.’)

A shallow foundation is a type of foundation, which transfers building loads to the earth very near the surface, rather than to a much deeper subsurface layer, or a range of depths as does a deep foundation. Common Types of Shallow Foundations:

  • Spread Footings – also called pad footings are often square, are of uniform reinforced concrete thickness, and are used to support a single column load located directly in the center of the footing.
  • Strip Footings – (very similar to spread) also called wall footings are often used for load-bearing walls. They are usually long reinforced concrete members of uniform width and shallow depth.
  • Combined Footings – reinforced-concrete combined footings are often rectangular or trapezoidal and carry more than one column load.
  • Conventional Slab-on-Grade – a continuous reinforced-concrete foundation consisting of bearing wall footings and a slab-on-grade. Concrete reinforcement often consists of steel rebar in the footings and wire mesh in the concrete slab.

Spread footing foundations are common in residential construction that includes a basement, and in many commercial structures.


A piece of a broken gravestone, monument, or sculpture.


A structural framing system consisting of members joined together with moment or rigid connections which maintain their original angular relationship under load without the need for bracing in its plane.

Framed Opening

Headers or other structural members which surround an opening in a roof which can be for mechanical units, stairwells, etc.

Framing Plan

Floor or roof plans that identify individual marks, components, and accessories furnished by the joist manufactures in a detailed manner to permit proper erection of the joist and joist girders.

Free-Body Diagram

A diagram on which all of the external forces acting on a body are shown at their respective points of application.

Free Water

Water which can be taken on or lost by the soil without corresponding soil volume change.

Freeze-Thaw Cycle

The cycle of water freezing and later thawing and the effects it has on the material it is around or absorbed into often is a contributing factor to basement water problems.

French Drain

The moving of surface water away from an area. A drain that is used to collect water that migrates underground. It is not used to collect large amounts of water from a heavy rain fall. French Drains are usually dug down 36-48 inches. Then 1 1/4″ river rock is placed at the bottom of the trench and a 4″ corrugated pipe is placed over this rock. Once in place, the trench is filled with river rock to approximately 4-6″ below grade. The last 4-6″ are then topped with soil and/or sod.

Fill – Soil or sand brought in to raise the elevation of a building’s foundation and provide a level construction surface. Properly installed fill moves water away from the foundation. A perforated pipe installed in a cut to intercept and divert the underground water. The cut is below the level of the intruding water, and it is graded to drain the accumulated water away from the site. Sometimes a catch basin and discharge pump are required if a natural grade does not exist.


It is the speed of the oscillations of vibration and is expressed in cycles per second or Hz (Hertz).

Frieze– The middle horizontal member, as found in classical entablature. The architrave is located below, with the cornice being above the frieze.

Frost Heave

The raising of a soil surface due to the accumulation of ice in the underlying soil.A section of ruptured pavement caused by the expansion of freezing water immediately under the road.

Frost Heaving

Expansion that results when a mixture of soil and water freezes. Upon freezing, the total volume may increase by as much as 25 percent, depending on the formation of ice lenses at the boundary between the frozen and unfrozen soil.

Frost Line

The maximum depth to which frost normally penetrates the soil during the winter. The depth varies from area to area depending on the climate. In Connecticut it is 42″ below grade. In Maryland, D.C., and Virginia and Pennsylvania, it is 30-36 inches.


Striking a V-shaped trough in a bed of mortar.


Melting The melting of minerals at extremely high temperatures.



“G” Type Joist Girder

A type of Joist Girder where joists are located at panel points where diagonal webs intersect the top chord only.


The triangular portion of a roof located above the elevation of the eave line of a double sloped roof. The upper vertical triangular section, of the end of a building having a double sloped roof.

Gable Joist

A non-standard type of joist where the top chord is double pitched at an extreme pitch (say 3/12) and the bottom chord is straight or level.

Gable Roof

A type of roof containing sloping planes of the same pitch on each side of the ridge. A gable roof typically contains a gable at each end.


The thickness of a sheet of deck or the distance from centerline hole to centerline hole across a set of holes, usually perpendicular to the joist or joist girder.


The process of coating steel with zinc for corrosion resistance.

Galvanized Steel

steel coated with zinc for corrosion resistance.


A roof having two slopes on each side, the lower slope usually steeper than the upper one.

Gambrel roof

A type of roof containing two sloping planes of different pitch on each side of the ridge. The lower plane has a steeper slope than the upper. A gambrel roof usually contains a gable at each end, just like a standard gable roof.

Gap or Floating Floor

The space left in the cement, usually by the wall, to accept water from above floor level directly into the drainage system and also to allow for expansion and contraction of the floor.

Gap-Graded Soil

A coarse-grained soil containing both large and small sizes but relatively low proportion of intermediate sizes.


A main horizontal, primary structural member spanning between two main supports which carries other members or vertical loads.


A horizontal structural member that is attached to the sidewall or endwall columns supporting sheeting or paneling.


Hard course grained metamorphic rock, not easily worked. It is also known as a type of granite, composed of mica, quartz, and schist, with additional iron, magnesium and silicates.


The distribution of particle sizes, from course to fine, in a given sample of aggregate.


The ground elevation around a building. e level of ground surface. Also, the rise or fall per given distance (often per 100 ft or 30 m). Ground level, or elevation at any given point. Excavation or building up then leveling of soil that will support a building’s foundation. Correct grading causes water to drain away from the building’s foundation.

Grade beam

The grade beam is the concrete support that goes around the perimeter of a Pier & Beam foundation. This is what home and bricks are supported by along the perimeters. The concrete grade beam is, on average, poured 18-20 inches below soil grade and is reinforced with rebar laid inside the concrete for additional support. A foundation wall poured level with or slightly below the grade.


Grading is the term used to describe the direction water would flow on the soil. Traditionally, you want to have the soil graded away from the house at a rate of 1 inch of drop per foot of grading (often away from the home.)


Ceramic-coated colored crushed rock that is applied to the exposed surface of asphalt roofing products.


Geologically an igneous rock made up of mica, quartz, and feldspar. The predominant stone which was used in American monuments during the twentieth century. Most modern monuments and footstones are composed of granite, which is now imported in a wide range of colors from around the entire world.


Consisting of artificial stone of a fine granular structure.

Granular Disintegration

The final and most advanced stage of marble or limestone decomposition exhibiting, extensive sugaring and erosion with lost inscription. A highly weakened and deteriorated stone.

Green Roof

A roof of a building that is partially or completely covered with vegetation and soil, or a growing medium, planted over a waterproofing membrane. It may also include additional layers such as a roof barrier and drainage and irrigation systems.

Grillage Beam

A short beam used like a bearing plate to distribute large reactive loads to a wall such as the load from a joist girder.


Thin mortar used in almost liquid consistency, to fill joints or cavities solidly.


Highly plastic clay from the southern and/or western United States. Gumbo refers to a variety of fine-grained silty soils (usually clays).


The trough that channels water from the eaves to the downspouts.

Gusset Plate

A steel plate used to connect structural steel members or to reinforce members. It is usually inserted between the top or bottom chord of a joist or joist girder.


Gypsum is the more common name for a mineral compound called calcium sulphate dihydroxide. It is commonly used to manufacture drywall panels. A mineral consisting of the hydrous sulphate of calcium. Gypsum is used for a variety of purposes, but chiefly in the manufacture of plaster of paris, in the production of wallboard, in agriculture to loosen clay-rich soils, and in the manufacture of fertilizer. Plaster of paris is made by heating gypsum to 392°F (200°C) in air. A hemihydrate is formed as part of the water of crystallization is driven off. Later, when water is added, rehydration occurs. The interlocking, finely crystalline texture that results forms a uniform hardened mass. The slightly increased volume of the set plaster serves to fill the mold into which it has been poured.

Gypsum deposits are mined throughout the world, with the United States being a world leader in gypsum production. The majority of United States gypsum is mined in Michigan, Iowa, Texas, California, and Oklahoma. Canada is the world’s second largest producer. Most Canadian production is in the province of Nova Scotia. Among the other leading producers are France, Japan, Iran, Russia, Italy, Spain, and the United Kingdom.

Gypsum Crust

Calcareous stone sometimes degrades to form a highly decomposed incrustation, on its outer surface in areas protected from rainfall. If removed a crumbling stone is likely to be underneath.

If you have questions please call (877) 344-1155 or email sam@theFoundationExpert.com




Setting of concrete or mortar. May continue for months or years.


Is a measure of the resistance of a material to scratching and indention.


A fairly small board with a handle beneath it that is used for holding mortar.


A structural member located between two joists or between a joist and a wall which carries another joist or joists. Usually made up of an angle, channel, or beam with saddle angle connections on each end for bearing. A masonry unit laid flat with its longest dimensions perpendicular to the face of the wall. It is generally used to tie two widths of masonry together.


The outside point of a structural angle where the two perpendicular legs intersect.

High Strength Bolts

A structural steel bolt having a tensile strength greater than 100,000 pounds per square inch, usually A325 or A490.

High Strength Steel

Structural steel having a yield stress greater than 36,000 pounds per square inch.

Hinge Support

This type of support has one degree of freedom, it can freely rotate about its axis but it cannot displace in any direction. Two mutually perpendicular reactive forces exist at the hinge and their lines of action pass through the center of the hinge.


The inclined external angle formed by the intersection of two sloping roof planes. The hip runs from the ridge to the eaves.

Hip and Valley

A system of roof framing where support members form valleys and ridges.

Hipped Roof

A roof which slopes upward from all four sides of a building.

Hip roof

A type of roof containing sloping planes of the same pitch on each of four sides. A hip roof contains no gables. A roof which slopes from all four sides of a building. The line where two adjacent sloping sides intersect is called the ‘hip’.

Hip shingles

Shingles used to cover the inclined external angle formed by the intersection of two sloping roof planes.

Historic Pointing Mortar

A softer mortar designed for historic preservation. Contains a low percentage of Portland cement, such as a 1-4-8; meaning 1 part Portland, 4 parts hydrated lime, 8 parts sand, by volume. It may contain natural cement, or can be a pure lime mortar, with no cement present.


A chain or electric lifting device usually attached to a trolley which travels along a monorail or bridge crane.

Hollow Block Foundation

Block walls that have open hollow cavities designed within the block. These cavities allow water to collect inside the walls and cause a myriad of problems.

Homogeneous Material

A material having the same engineering design properties throughout.

Hooke’s Law

The linear relationship of forces and deformations, or stresses and strains.

Horizontal Bridging

A continuous angle or other structural shape connected to the top and bottom chord of a joist horizontally whose l/r ratio cannot exceed 300.

H-Series Joist

A series of joist adopted in 1961 so proportioned that the allowable tension or bending stress does not exceed 22,000 psi or 30,000 psi depending on whether 36 ksi or 50 ksi yield steel was used.


A moderate degree of wetness especially of the atmosphere. High relative humidity can result in wetness condensing on basement walls and floors, just as it does on other cooler things such as water pipes. The use of a dehumidifier and/or adequate ventilation is recommended to reduce or eliminate the effects of condensation.


The chemical reaction that occurs when water is added to cement, causing it to harden. Mineral hydration is an inorganic chemical reaction where water is added to the crystal structure of a mineral, usually called a hydrate. Hydration is the mechanism by which Portland Cement develops strength. The formation of a compound by combining water with some other substance. In concrete, the chemical reaction between cement and water. The chemical reaction by which a substance (such as Portland cement or plaster) combines with water, giving off heat to form a crystalline structure in its setting and hardening.


Active in the presence of, or under the influence of, water. Example; hydraulic cement hardens under water. Derived from the Greek ” hudor” ( water ).

Hydraulic Cement –Hydraulic cements are materials that set and harden after being combined with water, as a result of chemical reactions with the mixing water, and that, after hardening, retain strength and stability even under water. The key requirement for this strength and stability is that the hydrates formed on immediate reaction with water be essentially insoluble in water. Sometime referred to as “Hot Patch” because of the heat generated during its exceptionally quick curing time. Most construction cements today are hydraulic, and most of these are based on Portland cement, which is made primarily from limestone, certain clay minerals, and gypsum in a high temperature process that drives off carbon dioxide and chemically combines the primary ingredients into new compounds.

Non-hydraulic cements include such materials as (non-hydraulic) lime and gypsum plasters, which must be kept dry in order to gain strength, and oxychloride cements, which have liquid components. Lime mortars, for example, “set” only by drying out, and gain strength only very slowly by absorption of carbon dioxide from the atmosphere to re-form calcium carbonate through carbonatation.

Setting and hardening of hydraulic cements is caused by the formation of water-containing compounds, which form as a result of reactions between cement components and water. The reaction and the reaction products are referred to as hydration and hydrates or hydrate phases, respectively. As a result of the immediate start of the reactions, a stiffening can be observed which is initially slight but which increases with time. The point at which the stiffening reaches a certain level is referred to as the start of setting. Further consolidation is called setting, after which the hardening phase begins. The compressive strength of the material then grows steadily, over a period that ranges from a few days in the case of “ultra-rapid-hardening” cements to several years in the case of ordinary cements.


Chemical properties that draw or absorb water.


Repelling, tending not to combine with, or incapable of dissolving in water. Of or exhibiting hydrophobia.

Hydrostatic Pressure

“Still Water” pressure. Often caused by a high water table it is the pressure exerted against the foundation by various heights of water at rest. The same type of pressure you feel when you try to push a bucket into a pool of water. To some degree, this is the same pressure that allows gigantic ocean liners to stay afloat but this pressure has an adverse effect on the integrity of the foundation of a building.


A registered trademark of E.I. DuPont de Nemours, Inc., for a rubber roofing product, “chlorosulfonated polyethylene”.


A term that describes the behavior of a structural member subjected to reversed, repeated load into the inelastic range whose plot of load verses displacement is characterized by loops. The amount of energy dissipated during inelastic loading is indicated by the enclosed area within these loops.


ICBO (International Conference of Building Officials (Uniform Building Code)

A minimum model regulatory code dedicated to public safety through development and promotion of uniform codes and standards.

Ice Dam

A dam or blockage formed on a roof by the buildup of ice along the eave of a building. Ice dams occur when snow melts near the ridgelines of warm roofs (roofs without adequate ventilation). As the water runs down the roof to the overhang, it cools and freezes. If the snow continues this melt and freeze process, an ice dam can form that can seep under the shingles, through the decking and into the house. This, of course, can cause serious roof leaks–even in freezing temperatures. The best prevention to ice dams is a well-ventilated (cool) roof.

Additional protection for your roof can be applied with an impermeable ice and water membrane. The membrane is installed on top of the decking, under the roofing material. Temporary prevention of ice dams can also be done through the use of electric cables along the eaves of the roof (where the dams usually form). However, new ice dams can form above the cables and still cause extensive damage. Another emergency solution to ice dams is to fill a sock or nylon with calcium chloride. Lay the stocking vertically across the ice dam. The calcium chloride will melt the ice and release the water so that it can drain outside, and not inside your roof.

IFI (Industrial Fasteners Institute)Abbreviation.

Igneous Rock– Rock formed as molten magma cools and hardens under ground. Granite is the most common example, today being almost exclusively employed for monumental works. Course grained igneous rock are called granite and are preferred for monuments and building facades.

III (Institute of the Ironworking Industry


Impact Factor

The factor by which the static weight is increased by dynamic application.

Impact Load

A weight that is dropped or a dynamic load generated by movement of a live load such as vehicles, craneways, etc.

Impact Strength

The ability of a material to absorb the energy of a load delivered rapidly to a member.

Impact Wrench

A pneumatic device used to tighten nuts on bolts.


Beginning to take place.

Incised Carving

Decorative image or inscription cut into stone.

Inelastic Action

Deformation of a material which does not disappear when the force that produced it is removed.


Nonmetallic material which is entrapped in sound metal.


Replacement compound used patch or repair areas of lost or decayed stone, concrete, or masonry.

Injection Grout

A very thin grout which is injected or gravity fed into cracks or voids.


The inadvertent leakage of water, moisture, vapor or air into the building.

Inflection Point

Represent a point of zero moment in structural member.

Influence Line

An influence line is a curve whose ordinates give the values of some particular function (shear, moment, reaction, etc.) in an element due to a unit load acting at the point corresponding to the particular ordinate being considered. Influence lines for statically determinate structures are straight lines and for statically indeterminate structures the lines are curved and their construction involves considerable analysis.


On site, constructed or conserved in position.


A condition reached when a structure or structural member is loaded in which continued deformation results in a decrease in its load-resisting capacity.


Any material used to reduce heat transfer in a roof or building.

Intake Ventilation

The part of a ventilation system used to draw fresh air in. Usually vents installed in the soffit or along the eaves of a building.

Intensive (Green Roof)

A Green Roof with plantings such as trees and large bushes.

Interior Pier

When a slab foundation has dropped in an excessive amount and the elevations inside the home must also be brought up to an acceptable level, an interior pier is often used. The pier is placed under a load bearing wall and often under an interior beam support. Once the pier is in place, the hole is filled with dirt and the top is capped with concrete so it is less noticeable.

Intermittent Weld

A weld which is not continuous. It is broken by recurring unwelded spaces.

Interlayer Moisture

Water that is situated within the crystalline layers of the clay and provides the bulk of the residual moisture contained within the intermediate belt.

Internal Pressure

The pressure inside a building which is a function of the wind velocity and the number and locations of openings.

Interior Bearing

Bearing supports which are interior to two exterior supports.


The second of the three classical Greek orders, (Doric, Ionic, Corinthian). It was founded by the Ionic Greeks characterized by a spiral scroll, a volute.


A play of colors on the surface of a mineral, like a film of oil on water.

Iron Bacteria (The “Orange Stuff”)

An orange colored slimy substance, often mistaken for clay residue, that can clog drainage systems and sump pumps. It is actually a bacterium that feeds on the nutrients (iron ocher) of the flowing water. Chemical formulas, such as “Iron Out” will release the bacteria but be sure to follow label instructions. Another way to release the bacteria is by flushing the system with hot (140 degree) water.

ISO 9000 (International Organization for Standardization)

Is a series of quality management and assurance standards for companies to strive for.

ISO Board

Polyisocyanurate Board; a polyurethane foam supplied in board form primarily as an insulation material for the construction industry.


A material having equal physical properties along all axes.


J-Series Joist

A series of joist adopted in 1961 so proportioned that the allowable tension or bending stress does not exceed 22,000 psi and was made from A36 steel.

Jack Truss

A joist girder that is supporting another joist girder.

Jib Crane

A cantilevered boom or beam with a hoist and trolley used to pick up loads in all or part of a circle around which it is attached


A device which holds work or pieces of material in a certain position until rigidly fastened or welded during the fabrication process.


The area where two or more ends or surfaces are joined by a weld or other fastener.Any place where two or more edges or surfaces come to a union.

Joint Penetration

The minimum depth the weld metal extends from its face into a joint.


A structural load-carrying member with an open web system which supports floors and roofs utilizing hot-rolled or cold-formed steel and is designed as a simple span member.

Joist Designation

A standard way of communicating the joist safe uniformly distributed load-carrying capacities for a given span such as 16K5 or 24K10 where the first number is the nominal joist depth at midspan and the last number is the chord size.

Joist Girder

A primary structural load-carrying member with an open web system designed as a simple span supporting equally spaced concentrated loads of a floor or roof system acting at the panel points of the joist girder and utilizing hot-rolled or cold-formed steel.

Joist Substitute

A structural member which is intended for use at very short spans (10 feet or less) where open web steel joists are impractical. They are usually used for short spans in skewed bays, over corridors, or for outriggers. It can be made up of two or four angles to form channel sections or box sections.


Any of the small timbers or metal beams ranged parallel from wall to wall in a structure to support a floor or ceiling.

Joule The International System unit of electrical, mechanical, and thermal energy. A unit of electrical energy equal to the work done when a current of one ampere is passed through a resistance of one ohm for one second.



Knee Wall

Typically a short wall, usually under three feet in height. The term is derived from the association with the vertical location of the human knee. Usually found in basements where a crawl space was dug out or extended down and the knee wall, extends away from the original load bearing wall, approximately a foot or two, and then runs down to the floor approximately 3 feet in length or height.

Also commonly known as a half-wall, or partial-wall.


The top stone in an arch or the center stone in a flat span.

Kevlar (Trademark)

A synthetic fiber of high tensile strength used as a reinforcing agent for military and police applications, but also for structural applications. Usually meshed or intertwined with carbon fiber.

Kynar Coating

Architectural coating that is UV stable and suitable for exterior use on aluminum and other metal surfaces.


The distance from the outside fiber of a rolled steel beam to the web toe of the fillet of a rolled shape.

K-Series Joist

A series of joist adopted in 1986 based on a load/span type of determination.

KCS Joist

Is a K-Series joist that is designed to support uniform load plus concentrated loads or other non-uniform loads.


The width of a cut produced during a cutting process.

Key Plan

A small reference plan or outline of the whole building on each plan sheet divided into smaller areas for which each sheet is drawn. It can also show different sequences, phases, sheet number that area is drawn on, etc.

Key Way

A term used to indicate the notch made by a 2″ X 4″ piece of lumber, placed in the cement footing to keep the load bearing or foundation wall from slipping off the footing during pouring and curing. typically, a keyway is found in a wall made of concrete where there is two separate pours which abut themselves, otherwise referred to as a cold joint. it makes sense to insert a concave keyway continuously along the length and in the center of a section of the first wall section poured to receive an abutting concrete pour at a later date. this inserted keyway creates an interlocking style effect between the two abutting pours which creates a higher quality connection than simply butting the two pours with nothing to interconnect them.


A structural member used to brace a joist or beam usually at an angle.


SI prefix for 10^3 or 1000.


A unit of weight equal to 1000 pounds.

Knee Brace

A structural brace positioned diagonally between a beam or column and a joist panel point.

Knife Plate Seat

A vertical plate used as a joist seat whose width is small for bearing purposes. It is used for hip and valley bearing conditions, canted seat conditions, and extreme skewed conditions.

KSI (Kips per Linear Foot)

Is 1000 pounds per square inch.

KSF (Kips per Square Foot)

Is 1000 kips per square foot.

If you have questions please call (877) 344-1155 or email sam@theFoundationExpert.com




a layer of weak non-durable material containing cement and fines from aggregates, brought by bleeding water to the top of over wet concrete. Laitance may be detected by scraping the concrete surface with a putty knife; if a quantity of loose powdery material is observed or easily removed, excessive laitance may be considered to be present.


thickness built up in layers.

Laminated shingles

Strip shingles containing more than one layer of tabs to create extra thickness. Laminated shingles are also called three-dimensional shingles.

Laminated Stone

Built up in layers when formed, such as sandstone.

Lancet Windows

Tall narrow Gothic windows, characterized by sharply pointed tops.


To cover the surface of one shingle or roll with another.

Lap cement

An asphalt-based cement used to adhere overlapping plies of roll roofing.


Magma on the Earth’s surface.

Lava Rock / Lava Stone

A rock which originated as molten magma from beneath the earth’s surface and subsequently came to the surface as an extrusion, or remained below ground as an intrusion. The nature of the rock depends in part on the rate at which it cooled; as intrusions of magma slowly solidify, enough time elapses for large crystals to form whereas extrusions cool quickly, leaving little time for crystal growth. Thus, a coarse-grained, intrusive igneous rock has a fine-grained, extrusive counterpart; granite is coarse rhyolite and gabbro is coarse basalt. Igneous rocks are also classified as acid or basic, according to whether their silica content is high (e.g. granite), or low (e.g. basalt).

Leaded Glass Windows

A window having small panes of glass held in place by lead. Assorted decorative shapes were often combined with clear, etched, stained, and beveled glass. Commonly associated with church buildings, they were often incorporated into mausoleums of the very wealthy.


A structure depending upon another structure for support and having only one slope such as a shed.

Lean-to roof

A roof with one slope only that is built against a higher wall.


Pattern of stonework utilizing horizontal joints.


A green building rating system that stands for “Leadership in Energy and Environmental Design”. LEED is the nationally accepted standard for the design, construction and operation of high performance green buildings. LEED recognizes performance in five key areas sustainable site development, energy efficiency, materials selection, indoor environmental quality and water savings.


The flat projecting part of a structural angle.

Leveling Plate

A steel plate used on top of a foundation on which a structural column can be placed.

Licensed Engineer

Licensed by a state Board of Professional Engineers to practice the profession of engineering

Licensed Inspector

Licensed by a local, state, or Federal Board of Professional Inspectors to practice the profession of inspection. Construction Inspectors, Home Inspectors, etc.

Life-Cycle Cost

The total lifetime cost of a roof. Calculated by adding maintenance costs to the installed price, then deducting the added value the roof provides when the home is resold.


Produced by burning limestone in a kiln. The base for mortar.


A sedimentary rock formed from shells and organic sea matter. If metamorphisized becomes marble. Limestone was often used in nineteenth century monuments as a base. May be difficult to distinguish from marble, but tends to be grayer in color then the originally white marble.


A structure is said to behave linearly when its deformation response is directly proportional to the loading (i.e. doubling the load doubles the displacement response). For a material, linear means that the stress is directly proportional to the strain.

Linear Elastic

A force-displacement relationship which is both linear and elastic. For a structure, this means the deformation is proportional to the loading, and deformations disappear on unloading. For a material, the concept is the same except strain substitutes for deformation, and stress substitutes for load.

Line of Action

The line of action of a force is the infinite line defined by extending along the direction of the force from the point where the force acts.


A horizontal support for masonry or a stone spanning an opening; A horizontal structural member spanning a door, window, or other wall opening which supports a wall or any construction immediately above.

Liquid Applied Membrane

Generally applied to cast-in-place concrete surfaces in one or more coats to provide fully-adhered waterproof membranes which conform to all contours.

Live Load

Loads on a member that are not permanent and are likely to be moved at some point in the life of the structure. They can be loads produced by the use and occupancy of the building. These loads do not include dead load, wind load, snow load, or seismic load.


An external force. The force bearing downwards. The term load is sometimes used to describe more general actions such as temperature differentials or movements such as foundation settlements.

Load Bearing Capacity

Maximum load (weight) that can be applied over soil before it begins moving. Also called shear failure.

Load Bearing Columns

Columns built with or upon footings to support the weight of the building.

Load Bearing Wall

The walls which support the building structure. Sometimes referred to as the foundation, or foundation walls. Exterior walls which are built upon the footing are usually load bearing. Occasionally load bearing walls will run through the center of a home or building. Wall that helps support the weight above it, including a second story or roof. Example: Depending on the framing of a house or building, some walls are likely to be load-bearing walls, whereas non-load-bearing walls (partitions) merely define rooms or closets.


The direction extending along the long axis of the member.

Loose-laid Membranes

Membranes that are not attached to the substrate except at the perimeter of the road and at penetrations. Typically, loose-laid membranes are held in place with ballast, such as water worn stone, gravel pavers, etc.

Low slope application

Method of installing asphalt shingles on roof slopes between two and four inches per foot.

Low Temperature Flexibility

The ability of a membrane to resist cracking/remain flexible after it has been exposed to low temperatures. Roofing membranes encounter extreme weather conditions and resisting cracking at low temperatures is vital to the long-term performance of roofing membranes in colder climates. Low temperature flexibility is directly related to the amount of rubber incorporated in the membrane. Since the rubber modifier also increases UV protection, the better the low temperature flexibility, the greater UV protection a membrane will have. Therefore, low temperature flexibility is vital in warmer climates as well.

LRFD (Load and Resistance Factor Design)

A method of proportioning structural members such that no limit state is exceeded when all appropriate load combinations have been applied.


The way a mineral shines. It is affected by light reflecting off the surface of the mineral.



M Shapes

A hot rolled shape called a Miscellaneous Shape with symbol M that cannot be identified as W, HP, or S Shapes.

Major Axis

The axis of a structural member possessing the largest section modulus and radius of gyration, thus having the greatest flexural and axial compressive strength.


A spindle or an axle used to secure or support material being machined or milled.

Mansard roof

A type of roof containing two sloping planes of different pitch on each of four sides. The lower plane has a much steeper pitch than the upper, often approaching vertical. Contains no gables.


The ornamental or decorative facing around a fireplace including a shelf that is attached to the breast or backing wall above the fireplace. A beam or arch that supports the masonry above a fireplace; also called a mantel-tree. All the construction or facing around a fireplace.


A shelf built into masonry for ornamental reasons.


A beam or arch that supports the masonry above a fireplace.


The most common stone type used from the late 1700s in some areas through present day. Predominantly used during the Victorian era for gravestones, monuments, and sculpture. Most sought after in its purest white form of calcium carbonate. Unfortunately the stone most adversely effected be acid rain. Metamorphisized Limestone.


An identification number or method of relating to the erector which joist, joist girder or other separate part of the building goes at what location when being erected, i.e., J1, K25, L7, G12, or JG9.


A type of construction from materials such as concrete blocks, bricks, concrete, stone, or ceramic blocks which is laid unit by unit and set in mortar. Anything constructed of the materials stone, brick, block, concrete, tile, and mortar.


An asphalt-based cement used to bond roofing materials. Also known as flashing cement.

Material Safety Data Sheet (MSDS)

A written description of the chemicals within a product, and pertinent other data including such things as safe handling and emergency procedures.

Maxwell Diagram

A graphical method of determining stresses in a truss by combining force polygons of all the joints into one stress diagram.

MBMA (Metal Building Manufacturers Association)

An association of manufacturers of metal building systems whose objectives are to compile and publish recommended design standards which will insure high quality metal buildings.

MC Shapes

A hot rolled shape called a Miscellaneous Channel with symbol MC.

Mechanically-Fastened Membranes

Generally used to describe membranes that have been attached at defined intervals to the substrate. Mechanically fastening may be performed with various fasteners and/or other mechanical devices, such as plates or battens.

Mechanical Unit

An air conditioner or other unit either placed on top of a roof system or hung below which applies loads to joist or joist girders.


A decorative plaque with slightly projecting carvings.

Member Release

An idealization to model how members are attached to “each other”. It designates whether forces and moments at the ends of a member are considered fixed to or released from the member’s point of attachment.


A flexible elastomeric material applied to the exterior of the building.

Metal drip edge

A narrow strip of non-corrodible metal used at the rake and eave to facilitate water runoff.

Metal Building System

A building system consisting of a group of coordinated components which have been designed for a certain loading. These components are mass produced and assembled in various combinations with other structural materials to produce a building.

Metal Stud

A structural steel member used for framing walls just as a regular wooden one.

Metamorphic Rock

Rock formed or changed by heat and compression. Formed under high pressure and heat over a long period of time. Examples include Limestone becomes marble, shale becomes slate, and some sandstones become quartzite.


The action of heat and pressure.


A low floor between two stories in a building, usually just above the ground floor.

MHI (Material Handling Industry)

Is a not-for-profit organization which was formed to advance the interests of the material handling industry which includes the movement, storage, control, and protection of material and products throughout the process of their manufacture, distribution, consumption, and disposal.


Mineral that occurs in thin sheets and tends to sparkle. A major part of granite.

Mil / MIL

A measurement of thickness of paint. Measurement often used to determine thickness of a roofing membrane. 1 mil = .001 inch (1/1000) or 25.400 microns.


A surface which has been accurately sawed or finished to a true plane.

Mill Scale

Thin layers or flakes of metal that are usually remnants of the manufacturing process. Mill Scale should be removed prior to application of any product.

Mill Test Report

A report of a heat of steel that indicates the customer’s order number, grade of steel, number and dimensions of pieces shipped, and the chemical compositional makeup of hot rolled structural steel members. It also indicates physical properties, such as, yield strength, tensile strength, elongation, impact, and ultimate strength.


A solid mixture of chemicals that has certain regular characteristics, such as atomic structure and chemical composition.

Mineral-surfaced roofing

Asphalt shingles and roll roofing that are covered with granules.

Mineral Vein

Cracks in rocks that become filled with hot, mineral-rich liquids during their formation.

Minor Axis

The axis of a structural member possessing the smallest section modulus and radius of gyration, thus having the least flexural and axial compressive strength.

Miter Cut

A single cut made at an angle to the member length.

Modified Bitumen

A bitumen modified through the inclusion of one or more polymers (e.g., atactic polypropylene, styrene butadiene styrene, etc.). Composite sheets consisting of a polymer modified bitumen often reinforced as sometimes surfaced with various types of mats, films, foils and mineral granules.

Modulus of Elasticity (E)

Is the slope of the straight-line portion of the stress-strain curve in the elastic range found by dividing the unit stress in ksi by the unit strain in in/in. For all structural steels, the value is usually taken as 29,000 ksi. This is also called Young’s Modulus.

MOH’s Hardness Scale

A scale devised by the Austrian mineralogist Friedrich Mohs that measures the hardness of mineral by scratching. It is based on a scale which ranges from one to ten. Talc represents the number one, with diamond being at the top of the scale, as a ten in hardness.


Diffuse wetness that can be felt as vapor in the atmosphere or condensed liquid on the surfaces of objects; dampness. The state or quality of being damp. Generally refers to the presence of water, often in trace amounts.

Moisture Barrier / Vapor Barrier (See Crawl Spaces Waterproofing)

A non-porous material such as plastic or polyethylene sheeting that is used to retard the movement of water vapor into walls and attics and prevent condensation in them. A vapor barrier is also installed in crawl space areas to prevent moisture vapor from entering up through the ground. New elastomeric applications are now considered moisture barriers or the next generation of moisture barriers and waterproofing.

Moisture Content

The quantity of water in a mass of soil, sewage, sludge, or screenings; expressed in percentage by weight of water in the mass. The weight of water, usually expressed as a percentage of the total dry weight of a material. The weight of water in a given soil mass.

Moisture showing on basement walls.

This condition occurs during the hottest part of the year in unfinished or unconditioned basements. It usually is a result of high dew points. The first thing to check is the foundation drains; if they are blocked, water build-up around the foundation will also manifest itself in this way. But if the drains are open then it is almost always a result of the cold earth on one side of the foundation wall and the extremely moist humid air in the basement resulting in condensation on the walls. This condition disappears when the dew point falls below 55˚.

Mold / Molds (See Mold Detection and Remediation)

Name for certain multicellular organisms of the various classes of the kingdom Fungi, characteristically having bodies composed of a cottony mycelium. The colors of molds are caused by the spores, which are borne on the mycelium. Most molds are saprobes and can obtain moisture and nutriment from fruits, vegetables, jelly, cheese, butter, bread, silage, and almost any dead organic matter. Among the commonest forms is the black bread mold (Rhizopus nigricans), which grows on decaying vegetables and fruits as well as on bread. Some molds, e.g., species of Penicillium, are useful in the preparation of Camembert, Roquefort, and other cheeses. Penicillin and other antibiotic substances are also obtained from molds. A few molds are pathogenic, e.g., those which cause ringworm and other skin diseases and several which cause diseases of plants. Some molds produce toxic chemicals called mycotoxins that can cause serious diseases (see ergot). Some organisms traditionally thought to be mold (e.g., slime molds) have now been placed in the kingdom Protista.


The tendency of a force to cause a rotation about a point or axis which in turn produces bending stresses.

Moment Connection

A connection designed to transfer moment as well as axial and shear forces between connecting members.

Moment Diagram

A diagram that represents graphically the moment at every point along the length of a member.

Moment of Inertia (I)

A physical property of a member which helps define rigidity or stiffness and is expressed in inches raised to the fourth power. It is a measure of the resistance to rotation offered by a section’s geometry and size.

Moment Plate

A welded steel plate used to develop a rigid connection to the supporting member so that moment transfer can occur.

Monolithic Floor

When the floor and footing are poured together and become one single unit. The walls are then built on top of the floor. This is usually evident in a block foundation when the first block is a whole block with a mortar line under it on top of the floor.

Monolithic Pour

A continuous mass of concrete cast as a single piece. Only construction joints are used.

Monolithic Slab

A concrete floor and concrete foundation placed at the same time to form a monolithic footing and slab.


Usually a single rail support for a material handling system.


An open , longitudinally-fluted tapered steel tube, driven without a mandrel and filled as a cast-in-place concrete pile.

Montee Caisson

A steel caisson with sawtooth cutting edge, which is rotated to cut its way through rock. Loosened material is washed out of the caisson. More powerful motors and better cutting steels have brought a redevelopment of this once popular procedure.


From the root word meaning,” to think”. A building, structure or memorial; a headstone constructed of two or more sections. Can include a wide range of types and styles.


A plastic mixture of lime and sand, with possible other possible ingredients, such as horse hair; it is used chiefly for bonding masonry units together. Modern mortars include Portland cement.


The negative form, from which a cast is made.

MPC (Materials Properties Council)



A hot rolled structural tee shape with symbol MT which is cut or split from M Shapes.

Mudjacking / Mud Jacking / Pressure Grouting / Low Pressure Mud Pumping

Procedure in which grout (typically a sandy loam, water and cement mixture) is pressure pumped under the foundation in multiple locations. A process whereby a water and soil cement or soil-lime-cement grout is pumped beneath the slab, under pressure, to produce a lifting force which literally floats the slab to desired position.

Mud jacking is best used for small areas like driveways, sidewalks etc. It is not a good solution for a home or business foundation. The reason is that the applicator has no control over where the grout goes after leaving his equipment. The liquid material takes the path of least resistance so it can come up through the foundation in low areas and pipes that may not be firmly joined. In addition the back pressure from application can cause separation of plumbing pipes coming through the foundation. Because application is uneven results aren’t predictable. Once the grout has set up it is as difficult to remove as concrete. Mud jacking also tends to be a temporary method of repair. In order for the grout to hold the foundation in position it depends on the soil beneath it to remain in place. If the soil moves due to loss of moisture then the grout will not be able to hold the load.

When a home is repaired that has had a lift in excess of 2″, a gap is created under the slab. If this gap is not addressed, the concrete will begin to sag until it rests directly over the soil thus filling this gap. If this sagging occurs, excessive cracking will take place and it will have all of the signs of a foundation problem. Mud jacking is a process used to fill these voids and add additional support under the home’s foundation.

  • When the slab is raised less than two inches, this process is recommended to prevent any air pockets under the slab.
  • When the slab is raised more than two inches, this process is required to insure stabilization of the slab caused by the raising or lifting process.

Müller-Breslau Principle

Is a simple method to draw approximate shapes of influence lines. The Müller Breslau Principle is another alternative available to qualitatively develop the influence lines for different functions. The Müller Breslau Principle states that the ordinate value of an influence line for any function on any structure is proportional to the ordinates of the deflected shape that is obtained by removing the restraint corresponding to the function from the structure and introducing a force that causes a unit displacement in the positive direction.


A vertical member or division between the panels of a window.


A type of strong, thin polyester sheet used for producing blueprints of architectural drawings.

If you have questions please call (877) 344-1155 or email sam@theFoundationExpert.com


N Value / SPT Value

The number of blows required to drive a 2 in. O.D., 1 3/8 in. I.D, 24 in. long, split soil sampling spoon one foot with a 140 lb. weight freely falling 30 in. The count is recorded for each of three 6 in. increments. The sum of the second and third increments are taken as the N Value in blows per foot. (See ASTM D1586 – The Standard Penetration Test.)


Strips of lumber attached to the top chord of a joist so plywood or other flooring can be nailed at 36 inches maximum on center.

National Register of Historic Places

America’s official list of buildings, sites and districts which includes some cemeteries. It was founded by Congress in 1966, but is administered by the states.

National Roofing Contractors Association (NRCA)

An association of roofing, roof deck, and waterproofing contractors. The NRCA has the opinion that if an area retains water longer than 48 hours, it is not a roof; it is a pond.

Natural Bed

The surface of a stone, parallel to its stratification.

Natural Position

The natural position of a structure is determined by LASER levels, floor levels, and where the brick, doors and windows were originally placed on the slab.

NBC (National Building Code)

A minimum model regulatory code for the protection of public health, safety, welfare and property by regulating and controlling the design, construction, quality of materials, use, occupancy, location and maintenance of all buildings and structures within a jurisdiction.

NBS (National Bureau of Standards)


NCEES (National Council of Examiners for Engineering and Surveying)

Provides leadership in professional licensure of engineers and land surveyors.

NEA (National Erectors Association)



For joists and joist girders, when looking at the member with the tagged end to the right, it is the side you see first and is closest to you.


Reduction in area of cast-in-place concrete in a pile, either uncased or thin cased due to soil pressure or improper method of installation.

Needle Beam

A structural beam inserted through a hole in a wall to support the wall during underpinning, jacking or excavating operations beneath it. The beam transfers the wall load to a temporary or a newly installed foundation.

Needle Gauge

A pressure gauge with a needle stem for measuring air or steam pressure in pressure hose, by puncturing the wall of the hose with the needle stem.

Needle Gun

A hand held tool with a group of wired or needles in the end that vibrate when on and is used to clean a weld by beating the slag or covering from the welded area.

Needle Piles

Very small diameter slender driven steel tubular or rail section piles used in underpinning operations.

Negative Skin Friction

Side friction along a pile surface directed downward. Effect of settling soil that grips a pile by friction and adds a downward weight to the structure load. Also called Downdrag.

Neutral Axis

The surface in a member where the stresses change from compression to tension, i.e., represents zero strain and therefore zero stress. The neutral axis is perpendicular to the line of applied force.

Newel post

The post at the and bottom of the handrails and anywhere along the stair run that creates a directional change in the handrails is called the newel post. The newel post is securely anchored into the underlying floor framing or the stair stringer to provide stability to the handrails.


The SI unit of measure for force (N).

NFPA (National Fire Protection Association)

An international nonprofit organization to reduce the burden of fire on the quality of life by proposing codes and standards, research, and education on fire related issues.


Abbreviation for ‘Not in Contract’.

NIST (National Institute of Standards and Technology)

An organization that works with industry and government to advance measurement science and develop standards.

Non-Bearing Wall

A wall that supports no vertical load other than its own weight.

Non-Cohesive Soil

A soil in which there is no attraction or adhesion between individual soil particles

Noncompact Section

A steel section which does not qualify as a compact section and the width-thickness ratios of its compression elements do not exceed the values designated in the

Non-Displacement Piles

Piles formed by boring or other methods of excavation. H, open-end pipe and sheet piles are considered low-displacement piles.


A metal that does not contain, include or relate to iron.

Nonobstructed Pier

This is a pier that can be placed in the ground without any additional work (i.e. concrete removal, deck removal, etc.)


Not fit or suitable for drinking.

Nonrigid Structure

A structure which cannot maintain its shape and may undergo large displacements and would collapse under its own weight when not supported externally.


A sealant formulation having a consistency that will permit application in vertical joints without appreciable sagging or slumping. A characteristic which allows the sealant to be installed in a sloped or vertical joint application without appreciable sagging or slumping.

Non-Structural Elements

Elements of a building that are neither primary nor secondary structural elements, such as ceilings, mechanical and electrical equipment, and cladding.


a term used to describe fabrics, mats or scrims that are produced using processes other that weaving or knitting. Many nonwoven processes (i.e., spunbonded or wet laid, etc.) produce a random arrangement of reinforcing fibers (glass, polyester, etc.) in a mat or fabric.

Normal slope application

Method of installing asphalt shingles on roof slopes between 4 inches and 21 inches per foot.

NRCA (National Roofing Contractors Association)


NSPE (National Society of Professional Engineers)



Abbreviation for ‘Not to Scale’.



Observation Well

A perforated pipe installed in the ground for monitoring groundwater level.

Offset Ridge

When the ridge of a joist that has the top chord pitched two ways is not in the center of the member or bay.

One-third Increase

When designing steel members for forces produced by wind or seismic conditions, the allowable stresses in the design formulas may be increased 1/3 above the values otherwise provided.

Offshore Lead

A pile hammer lead which has an upper section wherein the hammer is contained and a lower section which closely fits about and guides the pile. The hammer is supported and aligned by the pile after engagement. The pile is usually supported by a template. Also called Cage, Can Lead, Church Lead, Rope, Suspended Lead, Pipe Lead.

On Grade

Placed directly on the ground, or leveled or excavated to the proper elevation.

On The Flat

A measurement of distance horizontally on a plan, no slopes involved.


Small, rounded grains that make up some sedimentary rocks.


The three Greek orders included, Doric, Ionic, and Corinthian. They were each symbolized by a specific style of column, capital, and entablature. Sometimes the orders were interchanged or combined in the same structure.

Order Lengths

Lengths of pile expected for the project, ordered by either the owner, the A/E or contractor from the supplier.


Rock or other material from which a metal is extracted.

Organic felt

An asphalt roofing base material manufactured from cellulose fibers.

Organic shingle

An asphalt shingle reinforced with organic material manufactured from cellulose fibers.

OSHA (Occupational Safety and Health Administration)

A federal organization whose purpose is to save lives, prevent injuries, and protect the health of the workers of America.

Oslo Point

A 3 to 5 in. shaft of hard steel is set into the lower end of an H-pile by slitting the shaft or cutting the web of the pile for some distance, and then welding the shaft to the H-pile. Utilized to secure a toe hold in sloping rock. Can also be fitted to end plate of a pipe pile.


A structural member which is usually perpendicular to a joist and attaches under the outstanding leg of one of the joist top chord angles. It then bears on a beam or wall and cantilevers across, similar to a top chord extension.

Outstanding Leg

The leg of a structural angle which is projecting toward or away from you when viewing.


Driving that exceeds the maximum warranted hammer blow count or damages the material comprising the pile. Hitting the pile more than the optimum or required number of blows per increment of advance. Continuing to drive after penetration of the pile is sped.


That portion of the roof structure that extends beyond the exterior walls of a building. The extension of the top chord of a joist beyond the outside of the bearing support.


Pack Out

When joists are erected in multiple bays, they begin to hit each other end to end (or pack out) because the center to center of beam is not true or the joists are too long.

Palletized Deck

Wood framed floating deck

Panel or Panel Length

The distance between two adjacent panel points of a joist or joist girder. A sheet of deck for a roof or floor.

Panel Point

The point where one or more web members intersect the top or bottom chords of a joist or joist girder.

Parallel Chord

Type of joist or joist girder which has its top and bottom chords parallel to each other. The member can be sloped and still have parallel chords.


The portion of a vertical wall of a building which extends above the roof line at the intersection of the wall and roof. In an exterior wall, the part entirely above the roof. A low protective wall that extends above the roofline or balcony for support.

Pargecoat / Pargeting / Parging / Parge Work

A coat of cement mortar on the face of rough masonry construction. Building codes require block walls to be parged at least up to the grade line. To not do so should, building with block below grade, and backfilling is a sure death sentence to that wall. Simply put this is coating a surface with mortar. It is also used when there are too many voids in a wall or the state of the wall itself has deteriorated so badly that it needs a uniform base so that it may be re-waterproofed. Elaborate plasterwork; especially an ornamental facing for plaster walls decorated with figures in low relief. The interior lining of a chimney flue used to improve its fire protection and to provide a smooth surface.

Partially Restrained

A type of connection that displays a moment rotation behavior that can neither be described as pinned nor fixed.


A wall that is one story or less in height used to subdivide the interior space in a building and can be a bearing wall or a non-bearing wall.


The SI unit of measure for stress or force per unit area (N/m^2).

Patching Compound

Composite mixture to infill lost stone.


The final surface texture or color. The protective crust which forms over time, on the surface of some types of stone outdoors.


Bricks in numerous sizes and shapes that are used for constructing sidewalks, patios, and driveways.

P-Delta Effect

The secondary effect of column axial loads and lateral deflection on the moments in structural members.


Abbreviation for ‘Professional Engineer’.


The highest point of a gable or also the highest point on a joist or joist girder where the sloped chords meet. See also Foundation Expert.


Triangular gable end of the roof, which is above the horizontal cornice.

Peel Strength

the average force (or force per unit width) required to peel a membrane or other material from the substrate to which it has been bonded.


A small enclosed structure above the roof of a building.

Percent Elongation

In tensile testing, the increase in the gauge length of a specimen measured at or after fracture of the specimen within the gauge length. This is usually expressed as a percentage of the original gauge length.

Perfect Cleavage

Property of mineral that breaks only in certain directions.


A unit of water vapor transmission, defined as one grain of water vapor per square foot per hour per inch of mercury (Hg) pressure difference (1 inch of mercury = 0.491 psi). Nice hairdo.


The rate of flow of a liquid or gas through a porous material.


A measure of how easily water penetrates the soil. Test of soil permeability is called a Perc or Percolation Test.


An official document or certificate by a governmental agency or building official authorizing performance of a building process or other specified activity.

Perpetual Care

Guarantee of eternal cemetery upkeep; funds were collected and set aside and sometimes markers were placed beside monuments, or inscriptions added to stones, to denote a payment had been collected.

Pier / Piering

A very wide pillar; a free-standing column; a vertical stone column that supports structures; a section of masonry used to carry weight from above, as in a arch, beams or girders. Multiple steel posts are driven through unstable soil to bedrock. Then hydraulic jacks are used to stabilize the slab. The slab is held in place by the pier and the special bracket, attached to the pier, that holds and supports the slab.

Pressed-Piling Pier – A pier system that is installed under the exterior grade beam of a structure for stabilization. The pier is placed directly under the grade beam of the structure using extreme pressure hydraulics and is driven straight down, as deep as necessary, to become embedded into solid strata and hold it securely in place. The press-piling pier will remain solid even with the excessive expansion and contraction of the soil around it. It is highly recommended for its stability and strength in all types of soil.

Double Eight Drilled Pier– A pier system that is used when “poured in place concrete piers” are required. The areas where pier placement is necessary, technicians dig holes, then drill shafts. Rebar is placed in the holes and the shafts are filled with wet concrete.

  • This type of pier system is most favorable for use on wing walls and other areas where periodic adjustment may become necessary.
  • In areas where stable soil is prominent, this type of pier system is optimal.

Termite Shields– A system that is installed in pier and beam foundations to prevent termites. Metal shields are placed between the pier and the floor system.

  • Used to prevent migration of termites and other insects.
  • Aids in the prevention of structural damage caused by termites, carpenter ants, etc.

Interior Pier or Re-shimming – A process that is used in pier & beam foundations to raise interior floor levels, and make simple floor level adjustments. Commonly used wood shims are replaced with high quality steel shims which are termite resistant.

Pier and Beam Foundation

A pier & beam foundation is a method of foundation using beams, joists, understructure supports and often a grade beam. This type of home is raised off of the ground using the grade beam and supports allowing access to plumbing and wiring. It is held straight using beams that run from one end to another at a span of 8-10′ on average. These beams have joists atop them running from one beam to the next. Then on top of the joists is the sub floor which we walk on. The use of this type of foundation requires a lot of wood and the existence of wood-rot is likely if the home does not have adequate drainage or if a plumbing leak exists.


Substances used as a coloring agent; originally made from natural products, but today include synthetic materials; coloring pigments are often used in paints, dyes, and in stone conservation to shade or color composite infill materials.


A column-like support, without a classical capital.

Pin Connection or Support

A connection where no moment is transferred from one member to another, only axial and shear forces. This type of support has one degree of freedom, it can freely rotate about its axis but it cannot displace in any direction. Two mutually perpendicular reactive forces exist at the pin and their lines of action pass through the center of the pin.


A hollow cylinder of metal used for the conveyance of water or gas or used as a structural column which comes in sizes of standard, extra strong and double-extra strong.

Pipe and stone – This is the most common type of foundation drain in use today. In general # 57 or # 67 washed gravel is put on top of the foundation drain pipe usually to a volume of ½ cubic foot. In a proper drain system this is covered with a non-woven filter fabric.

Pipe Bridge

A structural system where two joists are used to carry loads such as piping or ducts. The two joists have to have diagonal bridging and their top and bottom chords have to be laced together with structural members to provide stability for the whole structure,


Also known as “slope”, pitch is the measure of how “steep” a roof is. For example, if a roof is “4 in 12”, the roof rises 4 inches for every horizontal run of 12 inches. The pitch of the roof is a big factor in determining the kinds of materials that can be used and the longevity of the roof. Usually, a steeper roof (higher pitch) will last longer due to its better drainage capabilities. Is the slope or inclination of a member. It is defined as the ratio of the total rise to the total width. It also is defined as the angle that the top chord makes with the lower chord. There can be single or double pitched members. To use a chisel to square a stone. A stone chisel.


Distinct depressions on a stones surface.


A reinforced or enlarged portion of a masonry wall to provide support for vertical roof loads or lateral loads on the wall. An attached pier or pillar, often with a capital and base; a pier built in a wall to strengthen against horizontal forces or for appearance.

Plan North

The North arrow symbol on a contract drawing usually 90 degrees to the longitudinal axis of the plan so that communication will be easier for the elevations of the building, sections, etc.

Plane Frame

A two-dimensional structural framework.


Capable of being molded, formed, modeled, or spread, like a mortar or paste.

Plastic cement

A compound used to seal flashings and in some cases to seal down shingles as well as for other small waterproofing jobs. Where plastic cement is required for sealing down shingles, use a dab about the size of a half dollar unless otherwise specified.

Plasticity Consistency

A sluggish flow without segregation.

Plastic Design

A design concept based on multiplying the actual design loads by a suitable load factor and then using the yield stress as the maximum stress in any member.

Plasticity Index (PI)

A dimensionless constant which bears a direct ratio to the affinity of the soil for volumetric changes with respect to moisture variations. The PI is determined as the difference between the liquid limit (LL) and the Plastic Limit (PL).


A thin, flat piece of metal of uniform thickness usually over 8 inches to 48 inches in width.

Plate Girder

A built-up structural beam.

PLF (Pounds per Linear Foot)

A unit of load obtained by multiplying pounds per square foot times the tribituary width on a joist.


A block that raises a monument or sculpture.

Plinth Course

The projecting course of masonry often called the water table.


A rod, plate, or angle welded between a two angle web member or between a top or bottom chord panel to tie them together usually located at the middle of the member.

Plug Weld

A weld in a slot in a piece of steel which overlaps another piece. A principle use for a plug weld is to transmit shear in a lap joint.


Straight up and down; vertically perpendicular as measured with a spirit level, or plumb bob.

Plumb Bob

A weight, attached to a line used to establish a plumb point on a surface.

Plumbing Report

When a home is repaired, a plumbing report should be included to prevent problems from not being aware of existing damage. A report is done both before and after repairs on slab repairs and only after the repairs are completed on pier & beam repairs. The reports will be taken to test both high pressure and sewage lines to detect leaks.

Plumb Line

To extend a line forms the top to the bottom of a structure.


The number of layers of roofing i.e. one-ply, two-ply.


The process of filling in joints; by inserting mortar, after masonry has set.

Pointing Trowel

A small towel used for filling in small holes and for pointing up work.

Poisson’s Ratio

Defined as the ratio of the unit lateral strain to the unit longitudinal strain. It is constant for a material within the elastic range. For structural steel, the value is usually taken as 0.3. It gradually increases beyond the proportional limit, approaching 0.5.

Polar Moment of Inertia (J)

Is the sum of any two moments of inertia about axes at right angles to each other. It is taken about an axis which is perpendicular to the plane of the other two axes.


The gathering of water at low or irregular areas on a roof, or on soil.

Poorly Graded Soil

A coarse-grained soil in which a majority of particles are of one size. Often described as uniform or gap-graded.


The density of substance and its capacity to pass liquids.


The finest of all ceramics, it retains its strength even when very thin. Photographs of deceased were affixed onto monuments in porcelain frames or lockets.

Portal Frame

A rigid frame structure which is designed to resist longitudinal loads where diagonal bracing is not permitted. It has rigidity and stability in its plane.


A monumental projecting porch with a roof supported by columns. They were most commonly found at the front entrance of an important building or structure.

Portland Cement (See History of Basements; Understanding Residential Construction)

A cementitious binder used in most modern structural concrete; manufactured by grinding and “burning” a mixture of limestone with clay or shale with a small amount of gypsum. It is mixed with water and an aggregate (such as sand and/or gravel) to form a thick, heavy liquid that dries as a monolithic product. Although cement was developed by the ancient Romans, Portland cement was first developed in England in 1824; since then, its tensile strength has greatly increased. A mixture of certain minerals which when mixed with water form a gray colored paste and cure into a very hard mass. Cement most often used in modern construction to formulate concrete, mortar, and pre-cast products. Creates a very hard solid, not recommended for most aspects of historic preservation.

Positive Drainage

Positive drainage is the expression used to describe the soil laid around the perimeter of the home in a way that water moves away from the house. Minimum grading is a 2″ drop over 2′. This prevents water from ponding around the perimeter of house causing migrating water and helps control the moisture content of the soil. The drainage condition of a roof where all water is gone from the roof surface within forty-eight hours of precipitation during normal drying conditions.

Pot Life

The time interval following the addition of an accelerator before chemically curing material will become too viscous to apply satisfactorily.

Pounds (LB or #)

A unit of weight.

Poured Concrete Foundations

Walls made by pouring concrete into forms, usually held together by tie-rods. When the forms are removed the tie-rods are clipped and this location often leaks because of thermal movement, the curing process and when water pressure is present.

Pour Stop

An angle used around the sides of a floor to contain the concrete when it is being poured.

Powder Actuated

A fastening method which uses a powdered charge to imbed the fastener into the member.

Precast Concrete

Any concrete member that is cast in forms at a place other than its final position in use.


To manufacture or construct parts or sections of structural assemblies beforehand that are ready for quick assembly and erection at a jobsite.


To keep safe from harm or injury; Historic preservation attempts to preserve our histories artifacts and objects from previous generations.

Press Brake

A machine used in cold-forming metal sheet or strip into a desired cross section or structural shape.

Pressed Piling Piers

A system of pressed piling piers is a series of concrete cylinders pressed into the ground to provide support for a concrete slab.

Pressed Piling Piers with Insert

A system of pressed piling piers with insert is similar to pressed piling piers with one significant difference. It is also a series of concrete cylinders pressed into the ground to provide support for a concrete slab. However, the concrete cylinders have holes in the center in which a metal rod or insert is placed.

Pressed Pier

In the early 90’s, an alternate method to repair the home emerged. People wanted a longer-term repair that was less volatile to the elements around it. A pressed pier is a pier that is, on average, 6-8″ in width made up of pilings that are 12″ in length. This pier is made up of individual pilings that are pre-pressed and pre-formed and is ready to be placed into the ground. These pilings are pressed into the ground using a hydraulic press. The pilings are locked together using either steel shims or a single piece of cable. The piers are pressed to refusal and below the volatile soil. Refusal is either bedrock, hardpan, a very large boulder or when the amount of soil built up under the pier becomes so compressed that it can no longer be pressed any farther due to friction. The average depth of these piers is 12-20 feet in the DFW area. This is the equivalent of placing a foundation on stilts thus making it less vulnerable to the volatile soil around it.

Pressure Checks– A service performed prior to and after repair. Prior to and after raising the structure, water supply line pressure readings are taken, using normal supply guidelines.

  • Leaking water supply lines can cause pooling under the structure.
  • Pooling water can create many foundation problems including but not limited to settling and slab fractures.

Pressure Relief System

Below grade drainage designed and installed to reduce the effects of hydrostatic pressure at a level below the basement floor.

Primary Members

This is the main load carrying members of a structure such as a beam or joist girder.

Principle of Superposition

States that the resultant is the algebraic sum of the effects when applied separately.

Primer or Paint

The initial coating of a member applied in the shop which is not a finish coat and only protects from rust for a limited time. A material of relatively thin consistency applied to a surface for the purpose of creating a more secure bonding surface and to form a barrier to prevent migration of components.


Sealing of a porous surface so that compounds will not stain, lose elasticity, shrink excessively, etc. because of loss of oil or vehicle into the surround.

Prismatic Beam

A beam with uniform cross section.

Profile Drawing

A drawing or diagram which shows the outline of a joist with dimensions and also maybe the web system configuration and bridging rows.


In roofing, any object or equipment which pierces the roof membrane.


The correct or desirable relationship between parts.

Proportional Limit

The point on a stress-strain curve where the linear relationship between stress and strain ends and usually coincides with the material yield point.

Pry Bar

Any tool used to lever or pry stone or heavy objects.

PSI (Pounds per Square Inch)

A unit of stress or pressure.

PSF (Pounds per Square Foot)

A unit of stress which to multiply the tribituary width on a joist by to get PLF.

Pumice Stone

A volcanic stone, finely ground and used for polishing.


A pointed steel tool used like a chisel to remove chips or stone. Historically the work-horse of stone cutting.


Usually a cold-formed horizontal structural member attached perpendicular to the joist top chord or main frames of a building for support of the roof deck.

If you have questions please call (877) 344-1155 or email sam@theFoundationExpert.com



A common crystalline stone. A major part of granite.


Metamorphic sandstone. A harder denser sandstone.


A rock bed. A place where rock is cut from.


Elastic compression of soil during pile driving. A term utilized in wave equation analysis.

Quick Test

A maintained pile load test with time intervals less than 20 minutes between adding load increments.


A condition rather than a type of soil. Generally, a fine granular soil temporarily supersaturated with rising water and acting as a fluid under pressure.


Radius of Gyration (r)

Is the distance from the neutral axis of a section to an imaginary point at which the whole area of the section could be concentrated and still have the same moment of inertia. Formula=The square root of (the moment of inertia in inches^4 divided by the area of the section in inches^2) expressed in inches.


The main beam supporting a roof system or a sloping roof framing member.


The edge of a roof which intersects the gable part of a roof.


Roofing application method in which shingle courses are applied vertically up the roof rather than across and up. Not a recommended procedure.


The supporting framing member immediately beneath the deck, sloping from the ridge to the wall plate. A diagonal member which forms the shape and structure of a sloping roof, and supports the roofing material above.


The inclined edge of a sloped roof over a wall from the eave to the ridge.

Rake Joint

To remove some of the mortar from a joint to a uniform depth, before it hardens.

RCSC (Research Council on Structural Connections)



The force or moment developed at the points of a support.

Rebar or Reinforcing Bar

Ribbed steel rods that are placed in forms of foundations, concrete walls, and footers. Concrete is then poured into the forms with rebar in place. Rebar strengthens the concrete.

Re-cover (overlay)

The installation of a new roof system over an existing system without removing an existing system.


The reactions which are not necessary for static equilibrium.


The condition reached when a pile being driven by a hammer has zero penetration per blow (as when the point of the pile reaches an impenetrable bottom such as rock) or when the effective energy of the hammer blow is no longer sufficient to cause penetration. When so stipulated, the term refusal or substantial refusal may be used to indicate the specified minimum penetration per blow. Overdriving of piles after essential refusal can damage them seriously.


An additional member added to a structural member to provide additional strength.


The process of strengthening a member with some additional piece of material.

Reinforcing Rod / Rebar

A steel rod that is used for reinforcing concrete or masonry.


Is a decrease in load or stress of a member under a sustained constant deformation.

Release tape

A plastic or paper strip that is applied to the back of self-sealing shingles. This strip prevents the shingles from sticking together in the bundles, and need not be removed for application.


A design made to relieve the flat surface. It can project or be incised.


The reconstruction or renewal of any part of an existing structure or building for the purpose of its maintenance.


Installing a new roof system on a building that is not new.


The reinstallation of a leaning, fallen, or damaged gravestone or monument.

Residual Stress

Pre induced stresses within a structural member due to uneven cooling of the shape after hot-rolling.


The capacity of a structure or structural member to resist the effects of loads or forces imposed on it.


To restore or make new again. More aggressive then conservation, restoration implies recreating what has been lost.

Retaining Wall

A wall designed to resist the lateral displacement of soil, water, or any other type of material. A structure that holds back earth. Retaining walls stabilize soil and rock from down slope movement or erosion and provide support for vertical or near-vertical grade changes. A retaining wall is used to support eroding soil in areas where the ground is volatile. They also help move water away from an affected area with the installation of a French drain at the base of it. These walls are also used to provide additional support to foundations that are built up using fill dirt etc.


To stir thoroughly again, so as to give a workable consistency.

Revival Styles

To employ classical styles in new architectural works. Greek, Egyptian, Romanesque, etc, became very popular in America throughout the mid 19th and early 20th centuries.


A fabricated fold or bend in a sheet of deck which projects up from a horizontal plane.


The highest point on the roof of a building formed by two intersecting slopes or the horizontal line made by the top surfaces of the two intersecting sloping roof surfaces. The uppermost, horizontal external angle formed by the intersection of two sloping roof planes.

Ridge shingles

Shingles used to cover the horizontal external angle formed by the intersection of two sloping roof planes.

Rigid Connection

A connection where moment is transferred from one member to another.

Rigid Frame or Structure

A structural framing system consisting of members joined together with moment or rigid connections which maintain their original angular relationship under load without the need for bracing in its plane.


Irregular stone used for fill or to hold against erosion.


The vertical distance from the bottom to the top of an entity.

Rising Damp

Moisture brought upwards through the forces of capillary action and evaporation.

RMI (Rack Manufacturers Institute)

An institute organized in 1958 by industry leaders as a not-for-profit trade association. Its mission is to advance standards, quality, safety, and general fitness for intended use of industrial steel storage rack systems.


Solid mixtures, or aggregates, of minerals.


A smooth solid round bar used for the web system of a bar joist.

Roller Support

This type of support has two degrees of freedom, it can freely rotate about its axis or displace in one direction in the plane. Only one reactive force exists at a roller which acts perpendicular to the path of the displacement and its line of action passes through the center of the roller.

Roll roofing

Asphalt roofing products manufactured in roll form.

Romanesque Revival

The Roman and Byzantine styles which were characterized by their massive size and often included the round arch. They were popular during the second half of the 19th century.

Roof Covering

The exposed exterior roof skin of a building which can be sheets, panels or other materials.

Roofing tape

An asphalt-saturated tape used with asphalt cements for flashing and patching asphalt roofing.

Roof Nav

A password-protected software tool accessible on the FM Approval website which allows users access to the roof-specific portions of the FM Approvals Guide. The Roof Nav tool can be used to search the FM Global Database to create a roofing assembly that meets the requirements of FM Approvals.

Roof Overhang

A roof extension that projects beyond the ends or sides of a building.

Roof Ridge

The top horizontal member of a sloping roof.

Roof Slope

Roof slope is the most important factor in roof design. The slope of a roof effects the interior volume of a building, drainage, style, and material used for the roof covering. If water collects on the roof (no or poor drainage), the cause is probably related to the slope. Slope is the angle made by the roof surface plane with the horizontal plane and expressed as the amount of vertical rise for every twelve inch (12″) horizontal run. For instance, a roof that rises four inches (4″) for every twelve inch (12″) horizontal run, is expressed as having a “four in twelve” slope; often written as “412.” Expressed as a percentage, the slope would be 33%, which is equal to 4 divided by 12. Also known as the Roof Pitch. Some common roof slopes and the terms that classify them are:

  • Flat Roof 2/12
  • Low Slope 2/12-4/12
  • Conventional Slope Roof 4/12-9/12
  • Steep Slope 9/12 and higher

Root Barrier or Barricade

A root barrier is an impermeable material that is inserted into the soil driven into the soil to a depth of approximately 3 feet. The barrier prevents tree roots from growing around or under a home’s foundation where they may rob the soil of moisture. Root barriers may be made from fiberglass, Plexiglas, or other materials. A root barrier is used when a large tree or a group of medium trees are placed too close to a slab foundation. Many trees require 50-500 gallons of water per day depending on their size, type and time of year. The roots of these trees will travel around and under the foundation and will draw moisture from these areas-especially during the hot & dry months. The result is a lack of moisture around the foundation walls and under the slab in these areas causing the soil to become compressed thus allowing the backfill to settle, and the affected area under the slab to settle – either possibly causing a foundation problem. The roots can also find their ways to plumbing sources i.e. bathrooms, kitchens, and especially stairwell drains. Once the smallest crack is created in the pipe for whatever reason, the root will then grow into the plumbing for a greater water source. This also causes additional plumbing problems. To prevent this from happening, a trench is dug along the perimeter of the home, cutting through the roots at the same time. Then a piece of 30″ steel is unrolled and placed in the trench to prevent the future growth of these roots back around and under the house. The trench is then filled back in and all foliage is put back into place.


A brick laid on its edge (face).


The horizontal distance from the eaves to a point directly under the ridge. One half the span.


Rough fragments, either natural or broken stone used in course masonry, or as fill in concrete or walls.

Running Bond

This is the same as common bond, with continuous horizontal joints, but the vertical joints are offset or inline.



A sedimentary rock made up of compressed sand. Formed from fresh water sediment. Extensively used in the form of brownstone throughout the Connecticut River valley from the late 1600s to about 1900.


Asphalt used to impregnate an organic felt base material.

SBC (Standard Building Code)

A minimum model regulatory code for the protection of public health, safety, welfare and property by regulating and controlling the design, construction, quality of materials, use, occupancy, location and maintenance of all buildings and structures within a jurisdiction.

SBS (Styrene Butadiene Styrene)Modified

Roofing material with a modifier of asphalt that enhances the bitumen’s ability to resist the effects of weather and aging.

Scab On

A member fastened or welded to another member for reinforcement.


The most advanced form of spalling.


To make scratches in mortar or cement, so the next coat has a stronger bond.


A metamorphic crystalline rock which easily splits along its bedding planes. Used to create gravestones in some geographic locations.

Scissor Joist

A non-standard type of joist where both the top chord and bottom chord are double pitched and parallel with each other. Screeding

The wood or metal straightedge used to strike off or level newly placed concrete when doing cement work. Screeds can be the leveling device used or the form work used to level or establish the level of the concrete. Screeds can be hand used or mechanical.

Scratch Coat

The first coat in infill, stucco, or plaster.


A long, very straight board used for striking off concrete.


The process of leveling the surface of a concrete slab by striking off the excess concrete.


The reinforcing fabric that acts as a carrier for polymer modified bitumen. The scrim contributes to performance characteristics of the finished product that include puncture resistance, tensile strength and fire resistance. The two primary fabrics for scrim include fiberglass and polyester. A combination scrim, which incorporates both of these fabrics, also exists.


An outlet in the wall of a building or a parapet wall for drainage of water from a flat roof. Any opening or drain in the side of a structure, flat roof, or downspout for the drainage of rain water.


A framed opening in a roof used for access to the roof from inside a building.

SDI (Steel Deck Institute)

An institute which brings uniformity to the design, manufacture, quality control, and construction practices applicable to cold-formed steel deck.

SEAA (Steel Erectors Association of America)

An organization that sets uniform standards among the many steel erectors and helps promote safety in the erection industry.


A material applied to exterior building joints. Sealants should be capable of withstanding continuous joint movement during all weather conditions without failing.

Seat Depth

The out-to-out depth of the end bearing shoe or seat of a joist or joist girder which is the distance from the top of the top chord to the bottom of the bearing seat angle or plate.

Section Modulus (S)

A physical property of strength of a structural member. It relates bending moment and maximum bending stress within the elastic range. Formula S=I/c where ‘I’ is the moment of inertia of the cross-section about the neutral axis in inches^4 and ‘c’ is the distance from the neutral axis to the outermost fibers.

Sedimentary Rock

Rock that forms at the Earth’s surface. It consists of layers or rock fragments or other substances that have been deposited on top of each other. Examples include; lake and river beds become sandstone, sea beds become limestone.


The tendency of particles of the same size in a given mass of aggregate to gather together whenever the material is being loaded, transported, or otherwise distributed.

Seismic Load

Are assumed lateral forces acting in any horizontal direction that produce stresses or deformations in a structural member due to the dynamic action of an earthquake.

Self-Sealing Strip or Spot

Factory-applied adhesive that bonds shingle courses together when exposed to the heat of the sun after application. Also known as self-sealing cement.

Self Tapping Screw

A mechanical fastener for attaching deck, panels, or other materials to a structure which taps its own threads in a predrilled hole.


That portion of roll roofing overlapped by the succeeding course to obtain double coverage.


A breakdown of when materials are to be made or delivered for a project with one following after the other.

Set Back

The distance from the outside edge of an angle or other member to the edge of a gusset plate or angle welded near the end.


The installation of a new monument; The process during which mortar or concrete hardens. Initial set occurs when the concrete or mortar has to be broken to change its shape. Rate varies greatly depending on the temperature, amount of sunlight, and specific masonry mix.

Setting Bar

Steel bar formed round, square, or the strongest, octagonal in shape. Constructed from two to six or more feet long. Used to lift, maneuver and handle heavy weights with a mechanical advantage through leverage; A monument is “set”, by being dropped down off a setting bar.

Setting Clamps

Firmly attached onto a die stone, the stone is then lowered without risk of chipping.

Setting Compound

Also known as monument setting compound. Available in gray, dark gray, brown, and white. The preferred material used to install new monumental works.

Setting Cushions

A spacer placed between stone sections. It may be composed of lead, plastic, or other hard materials.


Refers to part of a foundation sinking below its original elevation. Settlement is usually evidenced by interior and exterior cracks throughout the building. The drop of some portion of the foundation below the original as-built grade.


This term refers to a process or situation where part of a home’s foundation has moved below its original elevation. It usually results in interior and exterior cracks in various places throughout the home. It is caused by the home experiencing a loss of mass under the foundation which originally supported it.


An interior space, enclosed by walls, which extends through one or more stories or basement which connects successive floors and/or roof for elevators, dumbwaiters, mechanical equipment, etc.

Shaker Sill

A 4″ x 6″ treated lumber that is placed perpendicular to the floor joist to stabilize the floor system in pier and beam foundations.


Thinly layered soft stone of clay origin. Becomes slate if metamorphisized.

Shape Factor

The ratio of the plastic section modulus Z to the elastic section modulus S or the ratio of the plastic moment Mp to the yield moment My.


A condition or force causing two contacting parts of a material to slide past each other in opposite directions parallel to their plane of contact.

Shear Center

The point in a cross section of a structural member to which a load may be applied and not induce any torsional stress in the cross section.

Shear Diagram

A diagram that represents graphically the shear at every point along the length of a member.

Shear Release

A boundary condition which constrains a member end from axial displacement and rotation but allows movement in a direction perpendicular to the members longitudinal axis.

Shear Stud Connector

A steel device used in composite design which is welded to the top flange of a beam or top chord of a joist which transfers shear from a concrete slab to the supporting member.

Shear Wall

A wall that resists horizontal shear forces applied in the plane of the wall.


Exterior grade boards used as a roof deck material. “Step sheathing” is used alone or in combinations with solid sheathing for installation of tiles or shakes. Step sheathing allows air circulations under the tiles by using 1-by-6 or 2-by-6 boards that are evenly spaced so that air can move under the tiles or shakes.

Shed Roof

A roof containing only one sloping plane. This type roof has no hips, ridges, valleys or gables.

Shelf Life

Used in the glazing and sealant business to refer to the length of time a product may be stored before beginning to lose its effectiveness. Manufacturers usually state the shelf life and the necessary storage conditions on the package. The maximum time that packaged and unopened waterproofing materials can remain usable.


Cushion. Spacer placed between stone segments. May be lead, copper, plastic and can vary in thickness. A piece of steel used to level a joist seat. It can be a bent plate, flat plate or rod. A piece of wood to level up any or take up space.

Shipping List

A list that gives each part or mark number, quantity, length of material, total weight, or other description of each piece of material to be shipped to a jobsite.

Shop Drawings

Can also be called the erection plans or framing plans. The actual drawings used by a shop to fabricate a product which includes all dimensions, materials, tolerances, etc.


The process of temporarily supporting a structure or structural member with auxiliary members.

Shore A Hardness

The relative hardness of elastic materials such as rubber or soft plastics can be determined with an instrument called a Shore A durometer. If the indenter completely penetrates the sample, a reading of 0 is obtained, and if no penetration occurs, a reading of 100 results. The reading is dimensionless.

Shot Stone

Stone quarried with explosives.

Shrinkage cracks

These cracks occur mostly in poured concrete foundation walls. They are normal and usually will never exhibit any moisture at all. Occasionally they do require some maintenance. If this happens it is usually better to repair the crack from the outside if possible. This is usually determined by how much landscaping or hardscaping may be disturbed or destroyed by the dig up. They can be repaired from the inside but should be done by an experienced concrete technician.

SI (Le Systeme International d’Unites)

The international abbreviation for the International System of Units or metric system.

Side Lap

The lap at the sides of a sheet of deck and is attached by side lap screws or welds between supports.

Side Lap Screws

A screw used to connect the sides of two adjacent sheets of deck together, #10 being the standard size.

Side-View Diagram

A drawing or diagram which shows the outline of a joist with dimensions and also maybe the web system configuration and bridging rows.


A walkway that provides a direct, all-weather approach to an entry. The sidewalk can be constructed of poured concrete, laid stone, concrete pavers, or gravel contained between borders or curbs.

Side Wall

An exterior wall which is parallel to the ridge of the building.


The lateral movement of a structure when subjected to lateral loads or unsymmetrical vertical loads.


Containing silica ( quartz or sand ). Written also as silicious .

Sill Plate

Bottom horizontal member of the exterior wall frame. The sill plate sits on top the foundation. Sill plate is the term used for the 2×4 or 2×6 piece of wood that is placed along the top of the Perimeter Grade Beam on a pier & beam house. This wood is either pressure treated or oil dipped (much older homes) to prevent moisture from traveling from the concrete grade beam into the joists or beams. When the home is subjected to excessive water in a certain area, the sill plate will deteriorate and become rotten and require replacement. Often times this deteriorated wood will become compressed and cause cracking in the sheetrock of the roof and walls. Replacing the sill plate is tedious but necessary for the longevity of the foundation. The horizontal wood member that is anchored to the foundation masonry to provide a nailing surface for floors or walls built above.

Simple or Single Span

A span with supports at each end, no intermediate support, that restrain only against vertical displacement with the ends of the member being free to rotate.

Single Curvature

When moments produce a deformed or bent shape of a structural member having a smooth continuous curve or arc.

Single Slope

A sloping roof in one plane which slopes from one wall to the opposite wall.

Single-Ply Roof

A type of roofing system using thermoplastic membranes which are seamed by either hot air or solvent welding of one sheet to the next or using thermoset membranes which are seamed with an adhesive.

Silt fabric

A porous fabric that acts as a barrier between the backfilled soil (see backfill) and the gravel surrounding the drain tile. This barrier prevents soil particles from blocking the movement of ground water to the drain tile.

Single Coverage

Asphalt roofing that provides one layer of roofing material over the deck.

Single Ply

A descriptive term signifying a roof membrane composed of only one layer of material such as EPDM, Hypalon or PVC.

SJI (Steel Joist Institute)

The institute is a non-profit organization of active joist manufacturers that maintains sound engineering practice throughout the joist industry. The institute cooperates with business and government agencies to establish steel joist standards and does continuing research of their products to maintain the integrity of their products.


The condition when two entities come together at an angle which is not 90 degrees or perpendicular to each other.


An opening or roof accessory in a roof or ceiling for admitting light. If it bears across a joist, the top chord angles may be unbraced for design considerations.

Skin Friction

The resistance of the soil surrounding a pile to vertical movement of the pile.


One or another variety of concrete foundation that is supported entirely by the surface soils. It probably constitutes the majority of new residential construction in areas with high-clay soils.

Slab Foundation (See Understanding Residential Construction)

Slabs are generally cast monolithically with perimeter as well as interior beams that are designed to provide sufficient support for the entire structure as well as to provide stiffness to resist differential soil movement enough to limit cracking in the foundation and finishes. Slabs are typically reinforced with conventional reinforcing steel (re-bar) and/or post-tensioned cables that are installed throughout both the slab and beam portions of the foundation. It is supported entirely by surface soils. (Most homes built in Texas and Arizona are built on concrete slabs.)

Slab On Grade Foundation

A building construction practice in which the concrete foundation slab is formed from a reinforced form (typically a wood frame) set into the ground. The concrete is poured into the form.


A non-metallic byproduct of the welding process forming a hard crust over the molten steel which should be chipped away for inspection of a weld.

Slender Element Section

A steel section whose width-thickness ratios of any compression element exceeds the values of a noncompact section.

Slenderness Ratio

The ratio of the effective length of a column to the radius of gyration of the column about the same axis of bending.

Slip-Critical Joint

A bolted joint in which the slip resistance of the connection is required.

Sling Bar

Spreads slings apart, from which monuments are lifted with.


Constructed from polyester, nylon, or other very strong materials. Stone is hung from, in order to be raised, moved, or set.


The angle or inclination a structural member makes with reference to a horizontal position expressed in inches of vertical rise per 12 inches of horizontal run, i.e. 3/12. The degree of roof incline expressed as the ratio of the rise, in inches, to the run, in feet. Refers to thickness or moisture content in concrete.

Slot Length

The length of a slotted hole in a joist bearing seat or other structural connection.

Smooth-surfaced roofing

Roll roofing that is covered with ground talc or mica instead of granules (coated).

Snow Drift

The triangular accumulation of snow at high/low areas of structures expressed in PSF or PLF.

Snow Load

Are forces applied to a member by snow accumulation on the roof of a structure.

Soaker Hoses

Recycled rubber converted to a hose which allows water to pass in a low-volume, low-pressure form to evenly distribute moisture over a large area.

Soap Stone

A soft stone composed largely of talc. It carves easily and resists heat well. It tends to work more like a wood then a common stone. Occasionally gravestones were carved from soap stone.

Soffit / Lookout Block

Rake cross-bracing between the fly rafters and end gable rafters that the soffit is nailed to. The finished underside of the eaves.


All the loose material constituting the earth’s crust in varying proportions and including air, water, and solid particles. The solid particles have been formed by the disintegration of rocks.

The unconsolidated mineral or organic material on the immediate surface of the Earth that serves as a natural medium for the growth of land plants. (ii) The unconsolidated mineral or organic matter on the surface of the Earth that has been subjected to and shows effects of genetic and environmental factors of climate (including water and temperature effects), and macro- and microorganisms, conditioned by relief, acting on parent material over a period of time. A product-soil differs from the material from which it is derived in many physical, chemical, biological, and morphological properties and characteristics.

Soil is a natural body comprised of solids (minerals and organic matter), liquid, and gases that occurs on the land surface, occupies space, and is characterized by one or both of the following horizons, or layers, that are distinguishable from the initial material as a result of additions, losses, transfers, and transformations of energy and matter or the ability to support rooted plants in a natural environment.

The upper limit of soil is the boundary between soil and air, shallow water, live plants, or plant materials that have not begun to decompose. Areas are not considered to have soil if the surface is permanently covered by water too deep (typically more than 2.5 meters) for the growth of rooted plants.

The lower boundary that separates soil from the nonsoil underneath is most difficult to define. Soil consists of horizons near the Earth’s surface that, in contrast to the underlying parent material, have been altered by the interactions of climate, relief, and living organisms over time. Commonly, soil grades at its lower boundary to hard rock or to earthy materials virtually devoid of animals, roots, or other marks of biological activity. For purposes of classification, the lower boundary of soil is arbitrarily set at 200 cm.

Soil Belt

The vertical section that can contain capillary water available from rains or watering. Unless this moisture is continually restored, the soil will eventually desiccate through the effects of gravity, transpiration, and/or evaporation.

Soil Pressure

The load per unit area that a structure exerts through its foundation on the underlying soil.

Soil Stabilization

A procedure for improving natural properties of soil to make it a more adequate base for construction.

Soil Stack

A vent pipe that penetrates the roof.

Solar Absorptivity

Solar Absorptivity is a fraction which represents the difference between how much solar radiation is absorbed by a material versus that which is absorbed by a standard black surface. Since black (dark) surfaces absorb more solar energy than lighter colors (i.e., do not reflect as much), those surfaces are warmer.

Soldier Course

A course of brick laid with the brick standing on edge with the thin side on the face.

Solid Block Foundation

Block walls that are completely filled with cinder of concrete and have no hollow cavities and usually leak at the mortar joints.


In most of the pier & beam foundations built, the use of poured sonitube piers are used to support the beams that run under the house. They are placed 12-18″ under the soil grade and rebar is placed inside of the tubes for additional support. They are far superior and less susceptible to movement than “pad supports” which are stacked concrete blocks placed on an 8″ to 18″ pad which is usually placed on top of the ground.


Absence of the tendency to crack, swells, shrink, distort or disintegrate, under varying conditions.


To flake or split away, indicates the loss of stone. The crumbling or breaking off in small pieces of concrete or masonry usually as a result of the freeze-thaw cycle or deterioration (rusting) of reinforcing steel or tie-rods.


Describes surface failure in which chips are shed from a contact point. This is due to the maximal shear stress being not at the surface but just below it. One form of spalling occurs due to moisture freezing inside cracks in rock, cracking off the outer surfaces. Spalling can occur on a concrete surface if exposed to salt or if improperly finished.


The horizontal distance from eaves to eaves. The distance between supports which is the centerline of a beam, column, or joist girder or 4 inches onto a wall.

Spandrel Joist or Beam

A structural member at the outside wall of a building, supporting part of the floor or roof and possibly the wall above.

Special Design

A design required by a loading diagram or other special notes because a standard joist or joist girder cannot be specified from a load table.

Specialty Eaves Flashing Membrane

A self-adhering, waterproofing shingle underlayment designed to protect against water infiltration due to ice dams or wind-driven rain.


Detailed written instructions which, when clear and concise, explain each phase of work to be done. The detailed description of requirements, materials, dimensions, etc. of a proposed building or project.

Specific Gravity

The comparison of a minerals weight with the weight of an equal volume of water.

Specifying Professional

An architect or engineer, registered or licensed to practice professional architecture or engineering, as defined by the statutory requirements of the professional registration laws.


The connection between two chord members or other structural members joined at their ends by welding or bolting to form a single, longer member.

Spread Footings

Footings that generally consist of two structural components (1)steel-reinforced pads that are of sufficient size to adequately distribute the foundation load over the supporting soil and are poured at a depth to be relatively independent of seasonal soil moisture variation and (2) a steel-reinforced pier tied into the footing with steel and poured to the bottom of the foundation beam.

Sprinkler System

A system for fire protection usually consisting of overhead piping connected to a water supply to which automatic sprinklers are attached that discharges water in a specific pattern for extinguishment or control of a fire.


In deck terminology, it is the term for 100 square feet of deck or roofing surface. Formula number of squares = sum of(length of deck sheet in feet * width of deck sheet in feet * number of pieces)divided by 100. A unit of roof measure covering 100 square feet.

Square Cut

A cut to a structural member made at 90 degrees to the length of the member.

Square-Tab Shingles

Shingles on which tabs are all the same size and exposure.

SRI (Steel Recycling Institute)


SSPC (Steel Structures Painting Council)

A professional technical society whose primary objective is to improve the technology and practice of prolonging the life of steel and concrete structures through the use of protective coatings.

SSR (Standing Seam Roof)

A type of roof system where the deck is attached to clips which are then attached to the beam or joist. Usually this type of roof system cannot be counted on to provide lateral stability or support to the joist top chord.

SSRC (Structural Stability Research Council)



A hot rolled structural tee shape with symbol ST which is cut or split from S Shapes.


The property of a body to maintain its shape and remain rigid when detached from its support.


To make safe or secure. To prevent from falling or being damaged.

Stabilizer Plate

A steel plate at a column or wall inserted between the end of a bottom chord of a joist or joist girder to weld the bottom chord to or to restrain the bottom chord from lateral movement.

Stair rail

A sturdy handhold and barrier that follows the outside, and sometimes inside, perimeter of the stairs. The stair rail is used to prevent falls and to provide a means of additional support when walking up or down the stairs.

Stair riser

The vertical boards that close the space between each stair tread on a set of stairs (see stair stringer and stair tread).

Stair stringer

The supporting members in a set of stairs that are cut or notched to accept the individual treads and risers (see stair riser and stair tread).

Stair tread

The horizontal board in a stairway that is walked upon (see stair riser and stair stringer).

Standing Seam

Is a term used to describe the adjoining of two metal panels together with an upturned portion of the metal. The two panels are held together with concealed clips.

Star Drill

Chisel like drill, struck with a hammer and turned, then struck again, to slowly create holes in stone.

Starter Joist

A joist which is spaced close to a wall for deck support, usually 6 inches.

Static Equilibrium

A member or body that is initially at rest and remains at rest when acted upon by a system of forces.

Static Load

A load applied slowly and then remains nearly constant.

Statically Determinate

A member or structure that can be analyzed and the reactions and forces determined from the equations of equilibrium.

Statically Indeterminate

A member or structure that cannot be analyzed solely by the equations of statics. It contains unknowns in excess of the number of equilibrium equations available. Additional equations must be written based on a knowledge of elastic deformations.


A commemorative stone inscribed or sculpture, as a monument or set into the facade of a building.

Steep Slope Application

Method of installing asphalt shingles on roof slopes greater than 21 inches per foot.

Stem Wall

The vertical part of a concrete or masonry retaining wall.

Step flashing

Flashing application method used where a vertical surface meets a sloping roof plane.


A member used to strengthen another member against buckling or to distribute load or to transfer shear. Usually a flat bar, plate, or angle welded perpendicular to the longitudinal axis of the member.


The resistance to deformation of a structural member which can be measured by the ratio of the applied force to the corresponding displacement.


Any type of rock that has been selected or processed by cutting, shaping, or sizing for use in building construction or for decorative purposes; see brownstone, cobblestone, dimension stone, fieldstone, flagstone, freestone, granite, limestone, marble, pudding stone, rib vault, rusticated stone, sandstone, soapstone. In building construction, rock cut into blocks and slabs or broken into pieces. It comes as hard as granite and as soft as limestone or sandstone.

Where available, stone has generally been the preferred material for monumental structures. Its advantages are durability, adaptability to sculpting, and the fact that it can be used in its natural state. But it is difficult to quarry, transport, and cut, and its weakness in tension limits its use. The simplest stonework is rubble, roughly broken stones bound in mortar. Ashlar work consists of regularly cut blocks with squared edges. Building stone is quarried by sawing if it is soft, and split apart with wedges or by blasting if hard.

Many devices are used to shape and dress stone, from handheld tools to circular saws, surfacing machines, and lathes. Some stones are strong enough to act as monolithic (one-piece) supports and beams; and in some styles (e.g., ancient Egyptian temples) stone slabs are employed even for roofing, supported by many closely spaced columns. Before the arch, builders were handicapped by the tendency of stone to break under its own weight. But stone in compression has great strength, and the Romans built huge stone bridges and aqueducts. Though stone has generally been abandoned for structural use in the 20th century, it is widely used as a thin, nonbearing surface cladding


Measure of weight – mass BI ⅛ hundredweight = 14 lb (6.350 3~ kg). For centuries the major unit in the UK for expressing a person’s ‘weight’ (with pound the minor), the stone was removed from official UK measures in 1985.

Stone Foundation

Walls made of large stones stacked on top of one another and usually held together with a mortar type substance. This type of foundation is usually older and when the mortar deteriorates it allows more water to pass between the stones and not only cause water damage but structural damage as well. Because the stones are not all the same size and shape, the interior side of the wall is semi-smooth but the exterior side is not, which causes complications when trying to waterproof from the outside.

Stone Point

Sharp, pointed chisel for finishing stone faces.


That portion of a building which is between the upper surface of any floor and the upper surface of the floor next above.

Story Drift

The difference in horizontal deflection at the top and bottom of a story.

Strain Hardening

The condition when ductile steel exhibits the capacity to resist additional load than that which caused initial yielding after undergoing deformation at or just above the yield point.


The color of a minerals powder. It is often a more useful identification tool then color because it gives less variable results.


A very general term that may be applied to a material or a structure. In a material, strength refers to a level of stress at which there is a significant change in the state of the material, e.g., yielding or rupture. In a structure, strength refers to a level of level of loading which produces a significant change in the state of the structure, e.g., inelastic deformations, buckling, or collapse.


The intensity of internal force acting at a point in an object. Stress is measured in units of force per area. An internal force that resists a load. It is the intensity of force per unit of area, i.e., psi (pounds per square inch).

Stress Concentration

A localized stress which is considerably higher than average due to sudden changes in loading or sudden changes in geometry.

Stress resultant

A system of forces which is statically equivalent to a stress distribution over an area.


A brick or block laid lengthwise in a wall.


One of a series of parallel stripes or lines; with rock, formed by veins of minerals joining, may be considered blemishes or defects to be avoided.


Taking down or removing, as in the removal of forms.


In buildings, a structural member supporting stair steps.

Strip drains

This is a relatively new technology. It seems to be quite effective in most soil conditions. However, some failures have occurred in soils that are mostly red clay and have a large concentration of mica particles.

Strip shingles

Asphalt shingles that are approximately three times as long as they are wide.

Strong Axis

The cross section which has the major principal axis.

Struck Joint

A joint that has been made by pressing the mortar with a trowel.

Structural crack

This type of crack is usually 1/8″ or greater in width. It normally means there is a serious issue with the footing under the foundation wall. It should be looked at by a professional as soon as it becomes visible. There are several ways to repair this condition but the most popular method now in use is to install foundation jacks, not inexpensive but very effective.

Structural Engineer

The term structural derives from the Latin word structus, which is “to pile, build, assemble”. The first use of the term structure was c.1440. The term engineer derives from the old French term engin, meaning “skill, cleverness” and also ‘war machine’. This term in turn derives from the Latin word ingenium, which means “inborn qualities, talent”, and is constructed of in- “in” + gen-, the root of gignere, meaning “to beget, produce.” The term engineer is related to ingenious.

The term structural engineer is generally applied to those who have completed a degree in civil engineering specializing in the design of structures, or a post-graduate degree in structural engineering. However, an individual can become a structural engineer through training and experience outside educational institutions as well, perhaps most notably under the Institution of Structural Engineers (UK) regulations. The training and experience requirements for structural engineers varies greatly, being governed in some way in most developed nations. In all cases the term is regulated to restrict usage to only those individuals having specialist knowledge of the requirements and design of safe, serviceable, and economical structures.

Structural model

An idealization for analysis purposes of a real or conceived structure. A structural model includes boundaries limiting the scope of the analysis. Supports occur at these boundaries, representing things which hold the structure in place.

Structural Steels

A large number of steels that are suitable for load-carrying members in a variety of structures because of strength, economy, ductility, and other properties. Strength levels are obtained by varying the chemical composition and by heat treatment.


A mechanism designed and built or constructed of various parts jointed together in some definite manner to carry loads and resist forces.


A structural member used as a brace to resist axial forces.


Cement mortar or gypsum plaster of two or more layers; used to surface coat exterior or interior masonry walls or structures.


A wood or metal vertical wall member to which exterior or interior covering material may be attached. It can be either load bearing or non-load bearing.


Boards or plywood installed over joists on which the finish floor rests. Learn more about sub-floors.

Sub Foundation

The first layer of material placed in excavated ground prior to the foundation. May be composed of crushed stone, cinders.


The underlying material to which a finish is applied, or by which it is supported. A material upon which an adhesive, film, coating, etc., is applied. The surface, or material onto which systems are applied.


A partial vacuum due to wind loads on a building which cause a load in the outward direction.

Sump Pan

A metal deck accessory used at drain locations to close the opening where holes are cut in the metal deck.

Sump Pit

A hole dug to a depth that would accommodate a sump pump and serve as a collection receptacle for water. A sump well liner or crock is usually placed in the pit to keep the walls of the hole from collapsing and should have a bottom on them so dirt doesn’t get pumped out with the water and undermine the foundation.

Sump Pump

A pump designed to work in and under water to remove accumulations of liquid from a sump pit. A sump pump is used in conjunction with surface drains and French drains when the water that is being moved to a common point is lower than the designated outlet. Sump pumps are automatic and will automatically turn on when enough water has accumulated in its well. The water is then pumped to a designated area (i.e. street or lower spot below the foundation grade.) This method of removing water from around a home has been in use for many years. It is sometimes the only way to remove water from around the house especially if it is a full in-ground basement. It is also widely used where a daylight condition for the foundation drains is unobtainable. The most important thing in choosing a sump pump is determining how far the water must be pumped away from the house to effectively eliminate the threat of flooding. The size or Horse Power of the unit should be matched to the size of the pipe carrying the water away. If your home has a back-up generator this is one of the most important circuits to connect as it will usually be when the power is out that it is most needed.

Superimposed Load

Usually means a load that is in addition to the dead weight of the bar joists and bridging.


A support contributes to keeping a structure in place by restraining one or more degrees of freedom. In a structural model, supports represent boundary entities which are not included in the model itself, e.g., foundations, abutments, or the earth itself. For each restrained translation degree of freedom at a support, there is a corresponding reaction force; for each restrained rotation degree of freedom, there is a reaction moment.

Support post

A vertical framing member usually designed to carry or support a beam or girder. In newer construction a metal lally (pronounced “lolly”) column is commonly used, as well as 4×4 or 6×6 inch wood posts.

Surface Drain

A surface drain is used to move large amounts of water that collect on top of the ground. In most cases down spouts from rain gutters are also tied into the surface drain to help move water. A 4″ pipe is placed underground with collection boxes located at optimal areas which collect surface water and moved away from the affected area. These are the most common type of drain used to correct improper drainage or grading.

Surface force

A force applied to the surface of an object.

Surface Temperature

The temperature of the surface of the roof, wall, etc. of the project.


A boundary and/or topographic mapping of a site. A compilation of the measurements of an existing building. An analysis of a building for use of space. A determination of the owner’s requirements for a project. An investigation and report of required data for a project. The process of determining data relating to the physical or chemical characteristics of the earth, such as a land survey or topographic survey.


One who surveys or conducts surveys.


A drainage problem correction. A gently dug ditch, planted with grass, that will guide problem water away from a structure’s foundation.


The curvature of a structural member in the perpendicular transverse direction of its vertical axis.


Having the exact same forms or masses on either side of a center line or plane.

System of Forces

One or more forces and/or moments acting simultaneously.

If you have questions please call (877) 344-1155 or email sam@theFoundationExpert.com



Tagged End (T.E.)

This is the end of a joist or joist girder where an identification or piece mark is shown by a metal tag. The member must be erected with this tagged end in the same position as the tagged end noted on the erection plan.


The act of pounding, packing or consolidating as in concrete; The compaction of dirt during backfill.

Tangent Modulus

The slope of the stress-strain curve of a material in the inelastic range at any given stress level.


Tar and pitch, are viscous, dark-brown to black substances obtained by the destructive distillation of coal, wood, petroleum, peat, and certain other organic materials. The heating or partial burning of wood to make charcoal yields tar as a byproduct and is an ancient method for the production of both tar and pitch. Coal tar is a residue in the manufacture of coal gas and coke. By the application of heat, tar is separated into several materials, one of which is pitch. The terms tar and pitch are loosely applied to the many varieties of the two substances, sometimes interchangeably. For example, asphalt, which is naturally occurring pitch, is called mineral tar and mineral pitch. Tar is more or less fluid, depending upon its origin and the temperature to which it is exposed. Pitch tends to be more solid. When ships were made of wood, tar had numerous uses, and an available supply of tar was an important factor in maritime growth. Tar made vessels watertight and protected their ropes from deterioration. All but small quantities of the tar now produced is fractionally distilled to yield naphtha, creosote, carbolic oil, and other equally important crude products. Among the substances produced by refining the various crude materials are benzene, toluene, cresol, and phenol. Tar from pine wood is used in making soap and medicinal preparations. Pitch is used in the manufacture of roofing paper, in varnishes, as a lubricant, and as a binder for coal dust in the making of briquettes used as fuel. Coal-tar derivatives are used in the manufacture of dyes, cosmetics, and synthetic flavoring extracts.

Tar paper

Tar paper is a heavy-duty paper used in construction. Tar paper is made by impregnating paper with tar, producing a waterproof material useful for roof construction. Roofing felt, one common type of tar paper, is a glass fiber or polyester fleece impregnated with bituminous material (tar, asphaltic bitumen); it is produced in roll form. In some cases mineral material (e.g. sand) is applied on one side to help prevent the material from sticking together while in roll form and to provide protection from atmospheric conditions. A distinction is drawn between tarred board and bitumen board.

Tar paper is used, among other things, for waterproofing roofs to prevent ingress of moisture. It is used as underlayment for asphalt, wood (a.k.a. shake), or other shingles, or even gravel, since tar paper itself isn’t particularly wind- or sun-resistant. It is sold in rolls of various widths, lengths, and thicknesses (3 foot wide rolls, 50 or 100 feet long and “15 lb” and “30 lb” weights are common in the U.S.), often marked with chalk lines at certain intervals to aid in laying it out straight on roofs with the proper overlap (more overlap for flatter roofs).

It can be installed in several ways, such as: mechanical fasteners, or a combination of the afore mentioned. It is often applied with staples or roofing nails, but also sometimes applied in several layers with methods such as a torch, hot asphalt, cold asphalt (adhesive), non-asphaltic adhesives, and heat (torch, hot air) and additional hot tar.

Older construction sometimes used a lighter weight tar paper, stapled up with some overlap, as a water- and wind-proofing material, but modern construction uses 8 or 10 foot widths of “Housewrap,” one brand of which is Tyvek, which is extremely durable and wind- and water-proof since there are far fewer seams than with the 3 foot wide rolls of tar paper.

Workers using special “roofing shovels” to remove composite shingles as part of a roof repair. Roofing felt is here used as underlay between the wooden sheathing and exterior shingles.

Many new pitched roofs however use a TPO (thermoplastic polyolefin) membrane for increased protection against leaks. These membranes (which are usually made up of advanced fabrics) have advantages over traditional 1F roofing felt, in that they are more durable and less prone to puncture and tear. They are also lighter and stronger, though quite recent (2003) in the market. There are also breathable variations, which allow water vapor to pass through the felt; when used in conjunction with proper ventilation, they help minimize condensation in loft spaces.

Tear off

A term used to describe the complete removal of the built up roof membrane and insulation down to and exposing the roof deck.


A hot rolled shape with symbol T and is shaped like a “T”.


Adding water to mortar to bring back to a workable texture.

Temporary Structure

Anything which is built which will not become part of the permanent structural system and will eventually be removed before or after the completion of the structure.

Tensile Strength

The holding power or measure of adhesiveness of concrete, masonry or stone; power to resist the action of forces tending to pull apart. Contrasted with compressive strength, the power to resist crushing under direct pressure. The longitudinal pulling stress a material can withstand without tearing apart or the maximum tensile stress the material can sustain.


A condition caused by the action of stretching or pulling of a component.

Tensile Strength

Or ultimate strength, is the largest unit stress a material can achieve in a tensile test. The ability of a waterproofing material to resist being pulled or stretched apart to a point of failure. The maximum force a material can bear without tearing apart. Roofing membranes should have sufficient tensile strengths to resist the severe stresses caused by internal and external forces imposed on it. Thermal shock, caused by sudden heating or cooling of a membrane, causes stress that a roofing membrane must be able to withstand. The greater the tensile strength of a membrane, the greater resistance it will have to splitting, breaking or tearing.


The tactile and visual quality of a surface, regardless of its color.


Creating a particular finish, such as brushed, smoothed, etched or pockmarked.

Thermal Block

A spacer which has a low thermal conductance.

Thermal Movement

Movement, either expansion or contraction, caused by temperature changes. The measured amount of dimensional change that a material exhibits as it is warmed or cooled.


The horizontal component of a reaction or an outward horizontal force.


A rod, plate, or angle welded between a two angle web member or between a top or bottom chord panel to tie them together usually located at the middle of the member.

Tie Joist

A joist that is bolted at a column.


A rod (steel) used as a connecting member or brace to hold forms in place when pouring concrete walls that are clipped when removing the forms.


A long stone which extends across a wall.

Tilted Joist

A joist which is supported in a manner such that the vertical axes of the joist is not perpendicular with respect to the ground.


The outside points of each leg of a structural angle.

Toe of Fillet

The end or termination edge of a fillet weld. The end or termination edge of a rolled section fillet.

Toe of Weld

The junction between the face of a weld and the base metal.


A unit of weight equal to 2000 pounds.

Top Chord

The top member of a joist or joist girder.

Top Chord Bearing

The bearing condition of a joist or joist girder that bears on its top chord seat.

Top Chord Extension (TCX)

The extended part of a joist top chord only. This type has only the two top chord angles extended past the joist seat.

Torque Wrench

A wrench containing an adjustable mechanism for measuring and controlling the amount of turning force exerted when used to tighten nuts and bolts.

Torsion Loads

A load that causes a member to twist about its longitudinal axis. Simple torsion is produced by a couple or moment in a plane perpendicular to the axis.


Abbreviation for ‘Top of Steel’.


The ability of a steel to absorb large amounts of energy without being readily damaged.


A tall structure most often round or square, rises from the ground to a height above its entire surroundings.


Curving bars which form a decorative shape, within a Gothic window.


An opening over a door or window, most often for ventilation. It contains a glazed or solid sash which is often hinged or pivoted.


Crossing from side to side or placed crosswise.

Trap Rock

A dark-colored igneous rock of great weight and strength, including basalt, feldspar, etc.


The proper term to describe performing a conservation procedure.


A steel tool with a flat surface for buttering spreading, and smoothing mortar or concrete; comes in various shapes and sizes with specific names.

True Up

To make level or plumb.


The removal of soil moisture by vegetation.


A tributary is a stream or river which flows into a mainstem (or parent) river. A tributary does not flow directly into a sea. Tributaries and the mainstem river serve to drain the surrounding drainage basin of its surface water and groundwater by leading all the water out into an ocean or some other large body of water.

Tributary Width or Area

The design area which contributes load to a structural member. It is one half the distance between members on either side of the member.

Trimmer Joist

One of the joists supporting a header. The header applies a concentrated load at that point on the trimmer joist.


In general, a structural load-carrying member with an open web system designed as a simple span with each member designed to carry a tension or compression force. The entire structure act will act like a beam.


A hollow structural steel member shaped like a square or rectangle used as a beam, column, or for bracing. Usually the nominal outside corner radius is equal to two times the wall thickness.

Tuck Pointer

A long flat tool made in varying widths from ¼- ½ inch.

Tuck-Pointing Brick (mortar pointing)

Filling the joints in masonry with mortar by using a tuck pointer. A process used to repair the mortar and improve the appearance of the brick veneer on the exterior of the home. Special masonry tools and skilled technicians are used to place and color match new mortar to damaged areas in the existing brick veneer.

  • Structure settlement creates cracks on exterior walls in which mortar breaks away from the brick.
  • Cracked, broken and separated veneer should be repaired to restore the original beauty of the home.


A rotating sleeve or link with internal screw threads at each end and used to tighten or connect the ends of a rod.


A method for pre-tensioning high-strength bolts by the rotation of the wrench a predetermined amount after the nut has been tightened to a snug fit.


A corner tower which rises from the second floor or roof line.


UBC (Uniform Building Code)

A minimum model regulatory code for the protection of public health, safety, welfare and property by regulating and controlling the design, construction, quality of materials, use, occupancy, location and maintenance of all buildings and structures within a jurisdiction.

UL (Underwriters Laboratories, Inc.)

A non-profit product safety testing and certification organization.

UL label

Label displayed on packaging to indicate the level of fire and/or wind resistance of asphalt roofing.

Ultimate Load

The force necessary to cause rupture.

Ultimate Strength

The maximum stress attained by a structural member prior to rupture which is the ultimate load divided by the original cross-sectional area of the member.

Unbraced Frame

A frame providing resistance to lateral load by the bending resistance of the frame members and their connections.

Unbraced Length

The distance between points of bracing of a structural member, measured between the centers of gravity of the bracing members.

Unbraced Top Chord

The specific length where the top chord of a joist has no lateral bracing by deck, bridging, or any other means.


A layer of asphalt saturated (sometimes referred to as tar paper) which is laid down on a bare deck before shingles are installed to provide additional protection for the deck.


A notch or groove melted into the base metal next to the toe or root of a weld and left unfilled by weld metal.


Underpinning is the process of modifying an existing foundation system by extending it to or into subsurface strata that is deeper and more stable than the near surface soil that supports the existing foundation system. This is done to provide vertical support that is not present in the existing design. Methods of underpinning include the construction of footings, stem walls, driven piling or drilled piers such as helical piers.


Description of a joist which is suspended from upper support points where most of the mass of steel is below the actual support points.

Uniform Soil

Soil that contains a high proportion of particles with narrow size limits.

Uniformly Distributed Load

A load or force, for practical purposes, that may be considered constant over the entire length or partial length of the member.


Abbreviation for ‘Unless Noted Otherwise’.


The situation in which areas of the foundation (usually internal) are raised above the as-built position. This term refers to a process or situation where part of a home’s foundation has moved above its original elevation. It usually results in interior and exterior cracks in various places throughout the home.


The wind load on a member which causes a load in the upward direction. The gross uplift is determined from various codes and is generally a horizontal wind pressure multiplied by a factor to establish the uplift pressure. The net uplift is the gross uplift minus the allowable portion of dead load including the weight of the joist and is the load that the specifying professional shall indicate to the joist manufacturer.

Uplift Bridging

The bridging required by uplift design. Usually always required at the first bottom chord panel point of a K-Series, LH- or DLH-Series joist and at other locations along the bottom chord as required by design.

Upstanding Leg

The leg of a structural angle which is projecting up from you when viewing.

UV Resistance

The ability of a roof material to prevent degradation caused by exposure to Ultraviolet rays. Heat and UV are the two primary causes of premature roof failure. Oils in roofing membranes provide pliability. UV rays cause these oils dry out; this leads to the cracking of the roofing membrane. The addition of unique polymers maintains the membrane’s pliability which protects it from cracking and thus extends the waterproofing life of the membrane



The angle formed by two sloping sides of a roof. The internal angle formed by the intersection of two sloping roof planes to provide water runoff.

Value Engineering

The application of the Scientific Method to the study of selecting the optimum or best system that meets the need of the customer.

Vapor Barrier / Moisture Barrier (See Crawl Space Waterproofing)

A physical membrane which prevents moisture or water vapor from penetrating to the other side.

The phrase vapor barrier is often used to refer to any material, typically a plastic or foil sheet, that resists diffusion of moisture through wall, ceiling and floor assemblies of buildings. Technically, many of these materials are only vapor retarders as they have varying degrees of impermeability.

Water vapor moves into building cavities by two mechanisms diffusion through building materials and by air transport (leakage), which is usually far more significant and problematic.

In modern construction vapor barriers have become controversial and some out-of-date building codes may still require their use. Current building science recommendations are to locate the vapor retarder in the thermal envelope (exterior walls and ceiling/roof) depending on the climate zone. Heating-dominated climates require an interior vapor retarder. Cooling-dominated climates require an exterior vapor retarder. In mixed climates it is often better to have none. It is also important to allow water vapor to diffuse out of the building envelope (outward in heating climates, inward in cooling climates).

Basements – In sub-grade areas, particularly those formed in concrete, vapor retarder placement can be problematic, as moisture infiltration from capillary action can exceed water vapor movement outward through framed and insulated walls. If the foundation walls are properly waterproofed and have appropriate sub-surface drainage, then a warm-side vapor retarder and an air space (capillary break) between framing and concrete should offer sufficient protection against moisture problems.

Under concrete slabs – A slab-on-grade or basement floor should be poured over a cross-laminated polyethylene vapor barrier over 4 inches (10 cm) of granular fill to prevent wicking of moisture from the ground and radon gas incursion.

Vapor retarder

A vapor retarder and an air barrier, however, serve different functions and are not necessarily interchangeable.

Permeability, rated in perms, is a measure of the rate of transfer of water vapor through a material (1 perm = 1 grain/sf-hour per inch of mercury pressure. Vapor retarders have permeability ratings of 1.0 or lower. A more accurate, and useful, categorization of materials would be impermeable (≤1 perm), semi-permeable (>1 – 10 perms), and permeable (>10 perms).

Vapor retarders slow the rate of vapor diffusion into the thermal envelope of a structure. Other wetting mechanisms – such as wind-born rain, capillary wicking of ground moisture, air transport (infiltration) – are equally important

Vaulted Ceiling

A ceiling formed from a continuous arch, found in Roman, Classical and Gothic architecture and revival styles. A common technique employed in the 19th and 20th century for the construction crypts and vaults in cemeteries.

Varying Distributed Load

A load or force, for practical purposes, that may be considered varying over the surface of the member, for example a snow drift.


A layer or bricks or stones that serve as a facing.


Any outlet for air that protrudes through the roof deck such as a pipe or stack. Any device installed on the roof, gable or soffit for the purpose of ventilating the underside of the roof deck.


Ventilation and cross ventilation are one of the keys to long-term ownership of a pier & beam foundation. Proper ventilation helps maintain the desired climate in the crawlspace of the home. Texas State Code for ventilation is 1-square foot of ventilation per 150-squre foot of first level pier & beam foundation. So a 1500 square foot house should have a minimum of 10 vents located at optimal locations.

Vent Powered with a Hydrostat

Many pier & beam foundations have inadequate ventilation and/or drainage. The result of this is excessive moisture migrating under the home and remaining there. Long term moisture under homes causes rotten wood, upheaval, compressed soil and eventually a sagging foundation. A powered fan can be installed at an existing vent location which draws air out from under the home creating cross-ventilation. This cross ventilation helps in evaporation of moisture under the house in the soil, concrete and wood. The use of a hydrostat allows the fan to only turn on when moisture levels under the house reach pre-determined levels.

VG-Type Joist Girder

A type of Joist Girder where joists are located at panel points where vertical webs intersect the top chord only. This type of girder is used for ducts to pass thru since the joists do not interfere with their passage.


The oscillating, reciprocating, or other periodic motion of a rigid or elastic body or medium such as a floor when its position or state of equilibrium has been changed.


The internal frictional resistance offered by a fluid to change of shape or to the relative motion or flow of its parts.


To make glass-like, as vitrified clay, glazed surfaces, etc. Usually done by heating to fusion.


Otherwise known as Volatile Organic Compounds. These are strictly regulated by the EPA. They are present in most waterproofing membranes to one extent or another. They are highest in the asphalt and alcohol based products and lowest in the water-based products. The list of specific compounds can be gotten from the EPA.gov website, they are too numerous to list here.


These are any hole in a foundation wall that allows water to find its way into the structure. Shrinkage voids at mortar joints is one of the biggest culprits for water intrusion in block walls. The air space created from the movement or decomposition of stone, or the air space between particles or aggregates in a concrete or mortar.

Void Ratio

The ratio of combined volume of water and air to the total volume of the soil sample.


A spiral scroll forming the major element of an Ionic capital.


W Shapes

A hot rolled shape called a Wide Flange Shape with symbol W which has essentially parallel flange surfaces.


A vertical or near vertical structure which encloses or separates spaces and may be used to resist horizontal or vertical forces or bending forces.

Wall Anchor

A small piece of angle or other structural material that is usually bolted to a wall to which a starter joist or bridging angle is welded or bolted to.

Wall Covering

The exterior wall skin consisting of sheets or panels.


A flat ring of metal with a hole in the middle used to give thickness to a joint or to distribute pressure under the head of a nut or bolt.

Water Leaks

Water leaks are a major problem for home foundations. Usually the result from leaks in the plumbing system, they can contribute to water accumulation under a home. Water leaks can cause upheaval (swelling and expansion of the soil) and excessive settlement.


A term which refers to the process where a building component is made totally resistant to the passage of water and/or water vapor.

Water Repellant (Coating)

Coating or sealer applied to the surface of concrete and masonry surfaces to repel water.

Water Vapor

Moisture existing as a gas in air.

Water Penetration / Water Seepage / Water Leaks / Leakage

The condition where water enters the interior areas of a structure.

Waterproofing (See Basement Waterproofing)

Waterproofing is a science designed to keep water out of buildings, through the roofing, the siding, the foundation walls, and specifically, basements. Water, in its many forms, is the number one concern for residential and commercial properties in the U.S. and especially in the D.C. Metro Area. The source of water is primarily from rainfall, snowmelt, and sometimes irrigation on the surface. In many areas of Maryland, Virginia, and D.C., the groundwater table is near or above the basement floor level at various times during the year.

There are three basic lines of defense against water problems in basements: (1) surface drainage, (2) subsurface drainage, and (3) waterproofing on the wall surface.

The goal of surface drainage is to keep water from surface sources away from the foundation by sloping the ground surface and using gutters and downspouts for roof drainage.

The goal of subsurface drainage is to intercept, collect, and carry away any water in the ground surrounding the basement. Waterproofing, the final line of defense, is intended to keep out water that finds its way to the wall and floor of the structure, or in many instances involving existing structures, keep out water which is already finding its way through the wall, floor, or both. If you have water in your basement, Call Foundation Expert Today for a FREE, no obligation consultation and inspection.

Residential Basement Waterproofing

Water may enter a basement through various means including through joints, walls, or floors (See Causes and Solutions). Various basement waterproofing systems address these problems and are available with varying cost, effectiveness, and installation invasiveness, depending on what company you hire, their level of experience, and whether they have adapted new technology, instead of using older methods and materials, which are not as effective and are sometimes obsolete.

Components of a subsurface system can include porous backfill (sand and gravel / aggregate), drainage mat materials or insulated drainage boards, and perforated drainpipes (drain tile) in a gravel bed alongside the footing, or inside beneath the slab that drain to a sump or to daylight. We now have new polymer-based-materials, as well as more advanced membrane materials. Local conditions and a thorough inspection can determine which of these subsurface drainage system components, if any, are recommended for a particular site.

Exterior and Interior Waterproofing and Drainage – New and Existing Structures

Exterior and Interior methods of waterproofing walls, crack repair and stabilization, and crawl space waterproofing, have advanced considerably. Foundation Expert Waterproofing uses the latest, most advanced and proven systems and products available today. We are capable of completely waterproofing the basement envelope / environment, stopping water from getting in, from both sides – negative and positive (interior and exterior). Yes, according to Iowa State University, “basements are not designed to be waterproof”, because contractors do not have the experience, nor do they want to increase their costs. At Foundation Expert, we do know how to design and waterproof a basement.

  • Exterior or Positive side applications – Waterproofing materials like epoxy, polyurethanes, waterproofing cement, tar, rubber, pre-molded membranes, drainage mats, etc., are used to waterproof and vapor seal the walls before water can penetrate through to the inside. (Your builder actually had to do this to pass inspection to sell the home.) Proper installation of perimeter drain tile in gravel, alongside the footing, always below the floor slab level, should take care of drainage issues.

With existing structures, Exterior / Positive Side methods require excavation, sometimes down to the bottom or next to the foundation or footing (often called footer). Exterior methods of waterproofing can be very effective but are usually more expensive, sometimes prohibitive depending on the application, the company, and other factors. However, sometimes you have no choice. When structural issues are in evidence, outside excavation and repair may be the only solution recommended by an engineer (engineer’s report), necessary for a permit, and to be approved by a city, county, or municipal inspector.

  • Interior or negative side applications – Here, we are allowing the water to penetrate to a certain extent, and managing or stopping its direction or flow. Water, which enters at the cove, can be diverted to a sub-floor drainage system, which is New Residential Code in Maryland and Virginia (See Causes and Solutions). At the end of this drainage system is a sump pump or two, which discharges the water outside and away from the home. However, if water is coming through the wall, the fix is not so simple – a wall system has to be devised to manage that specific flow. When properly installed, the sub-floor, interior system may be just as effective or more so than exterior drain systems, often at a fraction of the cost. Sometimes, not!

Interior Drain Tile and Water Management Systems are commonly recommended to address water, which seeps through the cove (where the floor and wall meet) or through floor cracks. The procedure involves removing a portion of the floor along the perimeter foundation wall(s) about 12″ to 20″, digging a wide and graded trench, down to the bottom of the footing, laying round washed gravel, installing nothing less than 4″ A.D.S. perforated drain pipe, which is then surrounded with washed gravel at the base of the wall.

On Concrete Block walls, we then drill weep holes to bleed the hollow cores, at every core and mortar seam. (See Video) Then, we run a wall drainage mat, Miradrain® 2000R over the weep holes, which allows the walls to continuously drain, covering the stone with a vapor barrier, and finish up with a Portland cement finish. The drainpipe (also called drain tile See History of Basements) either drains to daylight, or into sump containers, with Zoeller Commercial Grade, Cast Iron Sump Pumps to discharge the water up, and outside the basement.

Advances in Construction Waterproofing

A building or structure needs waterproofing as concrete itself will not be watertight on its own. The conventional system of waterproofing involves ‘membranes’ and drainage. These rely on the application of one or more layers of membrane (available in various materials: e.g., bitumen, rubber, silicate, PVC, HDPE (High-Density Poly Ethylene), etc.) that act as a barrier between the water and the building structure, preventing the passage of water, and subsurface drainage. However, the membrane system relies on exacting application, presenting difficulties. Problems with application or adherence to the substrate can lead to leakage.

Over the past two decades, the construction industry has had technological advances in waterproofing materials, including integral waterproofing systems, new polymer-based-materials, as well as more advanced membrane materials. With new construction, integral systems work within the matrix of a concrete structure, giving the concrete itself a waterproof quality for the first time. There are two main types of integral waterproofing systems: the hydrophilic and the hydrophobic systems. A hydrophilic system typically uses a crystallization technology that replaces the water in the concrete with insoluble crystals.

Various brands available in the market claim similar properties, but not all can react with a wide range of cement hydration by-products, and thus require caution. Hydrophobic systems use fatty acids to block pores within the concrete, preventing water passage. New membrane materials seek to overcome shortcomings in older methods like PVC and HDPE. Generally, new technology in waterproof membranes relies on polymer-based materials that are extremely adhesive to create a seamless barrier around the outside or inside of a structure.

Water Table

The upper limit of the portion of the ground totally saturated with water. This is a major cause of below grade water leakage especially through the floor, cove and lower part of the walls of the basement. The upper surface of water saturation in permeable soil or rock.

Weak Axis

The cross section which has the minor principal axis.


The breaking down of rocks or masonry, by the action of various processes such as freezing and thawing and dissolving in water.

Weathering Steel

A type of high-strength steel which can be used in normal outdoor environments without being painted. Should not be used in corrosive or marine environments.


The vertical or diagonal members joined at the top and bottom chords of a joist or joist girder to form triangular patterns or 2) The portion of a structural member between the flanges.

Web Buckling

The buckling of a web plate.

Web Configuration

The arrangement of the actual web system of a joist or joist girder which can be shown with a profile view of the member.

Web Crippling

The local failure of a web plate in the region of a concentrated load or reaction.


Stone chips used for leveling. Metal tools used in conjunction with feathers to split stone by hammering on, when used in groups along a row.

Weep Holes

Holes generally drilled in the lower course of hollow block walls near the footing that allow water trapped inside the cavities to escape. The openings made in mortar joints that facilitate drainage of built-up moisture.

Welded Splice

A splice between two materials which has the joint made continuous by the process of welding.


The process of joining materials together, usually by heating the materials to a suitable temperature.


Is the ability of a steel to be welded without its basic mechanical properties being changed.

Welding Washer

A metal device with a hole through it to allow for plug welding of deck to structural steel.

Well-Graded Soil

A soil with a fairly even distribution of grain sizes—no excess of one size and no intermediate sizes lacking.

Wind Column

A vertical member supporting a wall system designed to withstand horizontal wind loads. Usually between two main vertical load carrying columns.

Wind Load

A force or lateral pressure in pounds per square foot that is applied to a member due to wind blowing in any direction.

Wind Uplift

The upward force exerted by wind traveling across a roof.


The direction or side toward the wind. Opposite of leeward.

Working Drawings

The complete set of architectural drawings prepared by a registered architect.

Working Load

Also called service load, is the actual load that is acting on the structure.

Working Point

The point where two or more centroid lines of structural members intersect.

WRC (Welding Research Council)

This organization conducts cooperative research in welding with interested scientific societies, government departments, and any company using welded products.

Wrought Iron

Decorative iron that is hammered or forged into shape by hand. Very popular during the 19th and early 20th century for fences and ornament. Almost a lost art, as very few artisans continue to practice this trade.

WSD (Working Stress Design)

A structural design method whereby a structural element is designed so that the unit stresses computed under the action of working or service loads do not exceed the specified allowable values.


A hot rolled structural tee shape with symbol WT which is cut or split from W Shapes.


A vertical stack of bricks one thickness wide; a veneer course.



Structural bracing which resembles the letter “X”.


A simple home automation system that operates using your regular power lines.


Yield Point (Fy)

Is the unit stress at which the stress-strain curve exhibits a definite increase in strain without an increase in stress which is less than the maximum attainable stress.

Young’s Modulus


“Z” Section

A structural section in the shape of a “Z” cold formed from a steel sheet.


Council rules regarding the uses that an area of land may be put to.


If you have questions please call (877) 344-1155 or email sam@theFoundationExpert.com