Foundation Wall Cracks and Floor Cracks
All concrete structures will crack to some extent. Concrete will crack due to tensile stress induced by shrinkage or stresses occurring during construction, setting, or use. Contractors pour walls, or build block walls, and before the concrete and/or mortar can cure properly, or adequately, up goes the rest of your home, and there is the stress we are talking about. In many large structures, expansion and contraction joints, or concealed saw-cuts, are placed in the concrete as it sets to make the inevitable cracks occur where they can be managed and out of sight. In residential construction this rarely occurs.
Concrete members may be put into tension by applied loads. The size and length of cracks is dependent on the magnitude of the bending moment and the design of the reinforcing at the point under consideration.
Shrinkage cracks occur when concrete members undergo restrained volumetric changes (shrinkage) as a result of curing or drying, self-generated shrinkage or thermal effects. Once the tensile strength of the concrete is exceeded, a crack will develop. The number and width of shrinkage cracks that develop are influenced by the amount of shrinkage that occurs, the amount of restraint present and the amount and spacing of reinforcement provided. Some cracks are immediately apparent, visible within 0 to 2 days of placement, while drying-shrinkage cracks develop over time.
The first determination should be whether the crack in question is structural or not. The answer is usually degree – usually a measurement of an inch. For example, if you take a plumb bob or 4’ level on a bowed wall, and the displacement from the crack to the floor is an inch; or if one side of the wall is in or out an inch, or if the crack is one inch or wider in width, than you probably have a structural issue, and upon that determination, we would request the services of our PE – Professional Engineer, which we have on staff (see NADER). Don’t take a chance. Call The Foundation Expert today and schedule an Inspection by one of our Licensed and Certified Staff Members.
Regardless, wall cracks, block cracks, cement cracks, and mortar cracks can be sealed effectively with the right diagnosis, and then if applied properly, the right product and system. Combinations of structural I-Beams, angle irons, waterproof and hydraulic cements, epoxies, urethanes, polyurethanes, carbon fiber, with or without Kevlar, and other products have been used for decades to fix structural cracks from the inside. However, it takes experience, and knowing which product to apply to your specific foundation material and situation.
One concrete wall is not necessarily identical in chemical properties as another. One concrete crack is certainly different from another. Carbon Fiber and other fixes have been applied to bridges, parking structures for decades, and for the last few years, to the residential market with tremendous success. We have carbon fiber products, and carbon fiber reinforced with Kevlar. We have carbon fiber stitches and staples to stitch and staple a wall or floor together, if we determine this is the correct approach and
Epoxies, elastomeric sealants, polyurethanes, and a few other excellent products have proven to be effective,when applied properly. We have also seen failures when other companies haphazardly apply these materials. There are a variety of systems which may be applicable in certain situations, although proper and adequate drainage, in our opinion (and those of most engineers), may possibly be a critical component of any solution.
Overkill is never enough when it comes to your foundation, falling short is not acceptable. Polyurethane foams, and waterproofing sealants that are elastomeric have some give as opposed to the rigidity but structural adhesion experienced with epoxy. Each is designed to seal walls to prevent moisture from passing through. Each has its differences which make them good, or not good enough of an, option to use based on experience.
If you have a block wall, sometimes your solutions are limited by what can be properly done. You either have to stop the water by waterproofing the wall, which truly means outside excavation, and depending on our analysis, maybe exterior drain tile to lower the hydrostatic pressure. We may only need to install an interior wall and floor management system, allowing the water to flow; this can sometimes be done by installing modern microbial vapor seal wall systems and directing it to a sub-floor drain tile system, and maybe using a dehumidifier or other types of systems which extract or manage the moisture from the air, which we always recommend for basements.
In the end, it is price; what you can afford and which solutions are appropriate and feasible. The solutions are many, some good, some great, some horrible, depending on the company (in our opinion). Also, the application. We can propose a solution or option for any situation and we are not only capable of the application, but would do so with excellence. I have seen, first hand, the flip-side of the coin – a builder, or sub-contractor for other companies install systems with no regard to whether it would work in 5-10 years, since they won’t be around.
Since all homes are different, and each problem is unique, often we propose a combination of materials and solutions, for example: to properly waterproof a wall we might suggest drain tile system, pump, epoxy with carbon fiber, or polyurethane. On another, a simple dig and seal from the outside. On another, an entire wall system (we have many) with a sub-floor drain system. On another, just a drain tile system, with a wall management system. Only a proper inspection can determine which solution works best for you. Find out now. Call The Foundation Expert today and allow one of our Licensed and Certified Inspectors analyze your situation and prescribe a permanent solution!
Basement Wall Damage
Soil Compaction Changes
When your home was built, an area approximately 6 to 10 feet from where your house is currently located was excavated, footings were formed, your walls constructed, etc. (See Understanding Residential Foundation Construction. Then that area was in most situations, backfilled with the same clay that was originally excavated. Damage to foundation walls is caused when marine clays are used as backfill. This practice is now prohibited, but County inspectors do not sit around job sites watching as crews place backfill. Code violations are something that we find on a regular basis when conducting inspections – and it does not matter if the home is worth $100,000 or $5,000,000. New Home Building Contractors love to skimp and save money wherever possible.
In any case, this soil was not properly compacted to what we call a pan hard density. It was loosely backfilled, and rightfully so. Otherwise, the compaction would have imploded the walls that were not fully cured to begin with. As the years went by, and your house aged, the soil around your home compacted. During dry periods, the clay shrinks, settles into the voids left by the moisture, and then when the moisture returns, swells again. Damage is caused from these yearly cycles of pressure exerted by shrinking and swelling of the marine clay in the backfill. Swelling pressure of the soil can be compounded by improper drainage around the house from rainwater.
Porous Concrete Block
When concrete block is exposed to water, the concrete block soaks up the water like a sponge, at which point, the acid starts to corrode and weaken the block and the mortar that holds it in place. This can ultimately result in a weakened block wall, which can then bow inwards.
Structural Wall Cracks
Depending on the extent of damage, foundation walls may need to be replaced while others can be repaired. Interior solutions can be wall bracing, I-Beams, Carbon Fiber, epoxy and polyurethane injections, interior drain tiles, and other types of repair. We now have interior elastomeric applications to waterproof concrete blocks from the inside, if the block is unfinished. Outside solutions involve excavation, crack repair, wall rebuilds, helical piers and anchors, home leveling, waterproofing, drain tiles, etc. To prevent future damage, the clay must be removed and the backfill replaced with, according to code, a minimum of fifty-one percent (51%) sand and/or gravel.
Indicators of Expansive Soil Movements
Listed below are indicators you can look for to determine possible expansive soil related movement and / or structural damage. The probability that your foundation has experienced some movement increases with the number of indicators observed, their frequency, and location in the structure.
- Diagonal(stair stepping) Cracks in brick walls. Cracks may go through brick or mortar and vary in width
- Sagging brick lines when sighting along a wall
- Bowed or non-vertical walls
- Separation of wood trim joints at corner
- Separation of concrete driveway, patio, or sidewalk from foundation
- Tilting of landscaping/retaining walls
- Cracks in sheetrock walls or ceilings
- Bowed or non-vertical walls
- Bottom of wall separating from the floor
- Cracks at wall corners
- Cracks above doors
- Sticking doors.(warped door frames)
- Sticking windows
- Sloping floor surface
- Cracks in ceramic or vinyl tile
- Cracks in concrete floor
Soil Moisture Changes
Observing soil moisture changes around your foundation is possible, but what about under it? Moisture can move from outside to under your foundation through a property of soils known as suction or capillary action. Soil suction is similar to placing just a corner of a dry, compressed sponge in contact with a puddle of water. In a short time, the sponge has drawn water throughout itself and grown in volume. While a water source is present, the sponge will continue to absorb water until it is saturated. If the water source is cut-off, then water already in the sponge will distribute itself evenly, but the sponge will not reach saturation.
Water can move horizontally and vertically through the soils under your foundation in a similar manner. As clay soils draw water to themselves, they too grow in volume (swell or heave) causing your foundation to move. Drying outside your foundation reverses the process. The moist soils will lose volume (shrink) as soil moisture moves out from under your foundation, the clay will crumble and settle into the voids left by the moisture, creating voids under the footing, causing the foundation to settle. Shrinking and swelling soil motions can lead to damaging your foundation and structure.
Structural problems, wall rebuilds, stairwell installations, egress window installations, outside dig and sealing of cracks – all of these may require excavation. Waterproofing in its purest form is outside excavation, sealing the wall with a waterproof and vapor proof material, installing a proper drain mat for the wall, and installing a proper drain tile system to alleviate any hydrostatic pressure build up against the wall. Then, backfilling with aggregate. The Foundation Expert can handle any size project. Allow us to resolve your foundation and structural problems with experience, quality, and a cost-effective approach. Get answers now. Call The Foundation Expert @ (877) 344-1155