Many homeowners have struggled with water in their basements, sometimes due to crack leakage. While the ultimate goal is to have a dry basement, repairs have often let them down. In this section, we will talk about foundation cracks and how to address them.
Years ago, it was common practice to address wall cracks with an epoxy injection. This application was done for numerous reasons including basement waterproofing, cosmetic crack repair and structural repair. Many times it was performed to satisfy a real estate transaction as a low cost fix. What we have found is that in most cases, it is a temporary fix. I’m not saying that injections don’t have a place in the basement waterproofing world, it’s just that you have to be educated about the pros and cons when considering this type of repair.
Most all cracks in foundations are due to movement of the foundation, whether it is lateral movement of the foundation walls or foundation settlement. Some cracks can be attributed to metal placement in the foundation as well as thermal expansion. Thermal cracks are typically hairline cracks.
Epoxy is a material that is very strong in relation to its weight and mass. Is an epoxy injection as strong as an 8 inch conrete wall? That is very debatable. Often times we see epoxied cracks that the epoxy itself has cracked. This is due to continued movement of the foundation. ANY injection is not a good structural repair for foundations and should never be recommended for this purpose.
Stop the movement. If a foundation crack is a symptom of a problem, you have to address the problem before you address the symptom. It seems like common sense right? If I cut my hand, I can keep wiping away the blood but until I treat the cut, what am I accomplishing? Depending on the cause of the crack, a repair can be recommended by a trained foundation expert.
Sometime later, polyurethane injections were introduced as a way of injecting cracks to stop the water. These were used instead of epoxy due to the flexibility of the polyurethane, meaning it won’t re-crack if the wall experiences minor movements. If a foundation continues to move, even polyurethane can separate and fail. This should only be recommended when it has been determined that there has been no significant movement in recent years.
Hydrophilic vs Hydrophobic There are 2 types of Polyurethane used when injecting cracks, hydrophilic and hydrophobic. Hydrophilic polyurethane can be used in wet locations and as a matter of fact, it requires water to have its expansive reaction. This allows injections to be performed on actively leaking cracks. Hydrophobic polyurethane requires an absolutely dry crack to be injected. When I say absolutely, I mean dry through the entire depth of the crack. Failure to ensure this may mean failure of the injection.
In my opinion, hydrophobic polyurethane is not a good choice for crack injections.
Bottom line. Be careful with injections, they have their time and place but don’t expect miracles.
Certified Foundation Specialist