Is your foundation crack structural?

If you walk around your basement, chances are you’ll find something that will look like a crack. If you have Stone Walls, chances are your home is over 150 years old. Terra Cotta Block or Brick? Probably around 80-120. Concrete Block or what most call cinder block? Maybe you have a new home, or one that may be as old as 70 years – I can usually guess the age of a home within 5 years according to the condition of the wall material. Poured concrete also can be brand new or 70 years old. I’ve seen 30 cracks on a home two years old.

Regardless of what material your foundation walls (and floor) are made with, over time, you should prepare for, become used to cracks – they’re a natural occurrence. The ground settles, the ground shrinks, and swells; the wall and floor materials shrink and expand due to changes in soil temperature and moisture content. They can be simple cracks, that some would call a ‘settlement crack’, that pose no immediate danger or discomfort; then there are those that leak water.

The first determination should be whether the crack in question is structural or not. The difference between the two is 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 as measured from the tip of the ‘bob’ or the end of the level – to the wall, then it probably is structural; 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.

Upon that determination, we would request the services of a PE – Professional Engineer, which we have on staff. You need an engineer or engineering company with a stamp of certification to make that determination whether something is or is not. I can look at a crack and state that it may be a footing crack. I may be 99% sure, but without exposing the footing in that area of the home or building, I’ll never say that I am certain. The only thing that makes you an expert is ability to recognize symptoms, diagnose the situation, and have done so thousands of times.

That requires experience, not a college degree. On the flip side, the stamp of Certification to operate legally does require a college degree. And each state requires a P.E. number. Our Registered and Certified Professional Engineer (PE) numbers are: in Maryland (No. 27311), Virginia (No. 030472), Washington, D.C. (No. 901612), and Texas (No. 64659).

To fix a structural wall crack, properly according to the engineer’s report, and subsequent permit (sometimes a bureaucracy wants changes done to proposed plans) – requires a contractor with the license, degrees, certifications, insurance, and most important, the experience to fix it with today’s 21st Century materials, not materials that may meet minimum standards for Building Code , but materials that will fix your foundation for as long as you live in the home.

When diagnosed correctly wall cracks, mortar cracks, block cracks, and cement cracks can be effectively sealed with the proper product, applied correctly. Combinations of structural I-Beams, angle irons, waterproof and hydraulic cements, epoxies, urethanes, polyurethanes, drainage and drain mats and sheets, and other products have been used for decades to fix structural cracks from the outside and just as effectively from the inside. However, it takes experience, and knowing from which direction, and which product to apply to your specific foundation material and situation.

One brick wall is different from another. They just are. One concrete wall is not necessarily identical in chemical properties as another. One concrete crack is certainly different from another. Carbon Fiber and CF with Kevlar, epoxies, and other fixes have been applied to bridges, railroad and highway tunnels, metro and subway tunnels, and parking structures for decades, and for the last few years, to the residential market with tremendous success and failure. We have used carbon fiber reinforced with Kevlar. But we also rebuild some of those walls – from the inside out or outside in.

One of our favorite single crack fix is expose the crack to the footing. Then inject polyurethane through ports sealing the crack; the next step is back it up with a drain system comprised of a sheet of Mirardrain™ fastened to the wall covering the crack on either side with a foot or two of m-drain, and up the wall to the top, usually about 7-8ft up by 3-4ft wide. We then run feed the drain sheet into the drain system under the floor, or put one in.

Epoxies, elastomeric sealants, polyurethanes, and a few other brand name products have proven to be effective, when applied properly. We have also seen our share of 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 be a critical component of any solution.

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. One can be more effective than the other. We like polyurethane for its elastomeric quality. I personally don’t believe epoxy to be stronger than a wall that is being pushed by soil. If the crack keeps expanding, it may become structural. In the interim, the polyurethane should stop the water. If it doesn’t, the Miradrain will manage it.

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 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 you choose or engineer you choose. Also, the application. Since all homes are different, and each problem is unique, we often propose a combination of materials and solutions. Only a proper inspection can determine which solution works best for you. The Foundation Expert dot com is our site and we are an Engineering and General Contracting Firm capable of any construction project, residential and/or commercial.

Sam, the Foundation Expert