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Education Center

Concrete Foundation Wall Cracks and How to Repair Them

Poured foundation foundations are one of the most common and durable types of foundations used to support buildings. They are used because they are durable, easy to construct and take less time to build than a masonry foundation wall. While a poured concrete foundation is very strong and durable, it can have many issues as well. The most common issue is with cracks that can leak water into a crawlspace or basement.

These cracks can occur due to conditions when the concrete is poured, soil conditions around the foundation as well the shape of the foundation itself. Typical foundation cracks, under 1/8” in thickness are expected, considered normal and not a major cause for structural repair. They can, however, be a source for water intrusion into the basement or crawlspace and should be fixed, whether actively leaking or not. It is our experience that an existing foundation crack will eventually leak at some point.

Diagnosing foundation cracks is pretty straightforward. In the case of an unfinished basement or crawlspace, they are easily seen because the foundation wall is exposed. In the case of a finished basement, cracks can be identified by finding the first point of entry into the basement and looking at the exterior of the building. Foundation cracks are predictable in that they almost always follow a relatively vertical path from the bottom of the foundation wall to the top and can be seen from the exterior where the foundation wall is visible above grade.

How to Repair Concrete Foundation Wall Cracks

If the basement or crawlspace foundation walls are accessible, a urethane crack injection is the preferred method of repair due to its high success rate and relatively low cost. Another advantage of the urethane material is that is expands to fill the entire crack, effectively stopping the water on the exterior of the building. Urethane crack repairs, once cured, remain slightly flexible as well so seasonal movement of the foundation wall caused by expanding soil conditions and frost do not compromise the repair.

If the basement space is finished, an exterior option may be preferred if you do not want to cut open the wall to expose the crack or if mechanical equipment like furnaces and water heaters are in the way. There are two typical options for exterior crack repair, a waterproof membrane or a sodium bentonite clay application. Both work exceptionally well, which one is best for you situation depends on a few factors.

Our staff, with their years of experience, can help determine which crack repair method is right for your situation. If you think you have a foundation crack, contact Midwest Waterproofing for a free consultation.