Foundation Crack Repair using a Polyurethane Injection


Many homeowners with basements will notice cracks in their foundation walls over time. Even if you don’t see any water seeping from a crack in your foundation wall initially, or efflorescence on your basement walls, over the years you might begin to have water seepage occur. Cracks in foundation walls can create leaks that end up generating mold or mildew in a basement, and it can also cause structural damage over time if not taken care of properly. 

Cracks in foundation walls are caused by soil outside the home shifting, settling, or expanding. When hiring a concrete crack injection contractor, make sure to ask them what kind of foundation crack injection they do, along with the pricing. A single injection, at Schmitt Waterproofing, can cost about $1,000. Pricing normally depends on the length of the crack and how many cracks there are that need to be injected. Injecting polyurethane, also known as urethane or grout, into a crack in a basement foundation wall is one-third of the cost of what it would be to excavate around the exterior walls and then waterproof the crack on the exterior of the home.

A polyurethane crack injection is used for non-structural cracks in foundation walls, such as vertical and diagonal cracks that are less than a quarter of an inch wide. Polyurethane itself is a fluid resin that is injected into concrete cracks. It goes from being a liquid to a solid within minutes due to a chemical reaction. Polyurethane crack injections can be done using low pressure, or “surface port” injections, or can be done using high pressure. At Schmitt Waterproofing we use low pressure surface port injections, which are around 20-40 psi. 

Low pressure injections use surface mounted injection ports to insert polyurethane into cracks. High pressure injections are done around 1500-3200 psi, and use an electric injection pump to fill gaps in walls with activated polyurethane. In either case, the polyurethane fills the cracks and expands 5-10 times its original volume. This creates an airtight and waterproof seal that will remain flexible.

Before injecting polyurethane into a crack, a flushing process is done to clean out the crack before injecting anything into it. This means one can inject the polyurethane into the crack regardless of the weather, or the condition of the crack, in the foundation wall. 

If there is structural movement in the crack a staple or strap can also be added that keeps the wall from shifting. Injections are not just limited to cracks in the foundation. If you are seeing water coming in around a sewer or waterline penetration in the wall we can also inject the area surrounding the pipe to create a water tight seal. 

For all of your foundation crack repair needs, call Schmitt Waterproofing today at 404-268-1040, or fill out an online form to set up a free estimate. It’s never too early to address your water seepage needs. We have a trained team that can help you find the right solution to your waterproofing needs at a great price.

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