When a homeowner thinks about waterproofing the basement, the immediate concern is the high cost that often comes with it. Typically, a basement wall crack is something that the homeowner will quickly notice but addresses until it becomes a severe problem. Thankfully, a low-cost and highly efficient solution exists to repair the leaking and structural cracks in poured foundations – low-pressure injection. This process has become the most practical crack repair solution for basement waterproofing and foundation repair contractors throughout Canada. However, to a homeowner unfamiliar with crack injection, such a simple and effective process may sound too good to be true.
The idea behind crack injection injects a liquid polymer (typically a two-part polyurethane or epoxy) into the crack. This process allows the material to travel throughout the void in the foundation, effectively filling the crack upon curing. Before injection, the crack is covered with a sealer (the best being an epoxy adhesive) to ensure that the injected material does not leak out the front of the crack.
The crack injection process has given homeowners an affordable solution to a problem that has the potential to be quite lingering when not adequately addressed. For example, in years past, the most common remedy for a leaking crack was to install an interior drain tile system or to excavate around the home – both requiring a significant amount of time and labor, resulting in high expenses to the homeowner. Crack injection is not only more cost-effective, but it is also an effective repair solution because it addresses the void areas that make up the crack, unlike drain tile, which only collects the leaking water while allowing the crack to remain open
One of the most common questions has to do with the injection material – which is better suited for foundation crack repair? Both polyurethane and epoxy work well, but specific parameters in which one material can be preferred in place of the other.
Most cracks form as a result of shrinkage – typically, it is not a matter of if, but a matter of when a foundation crack will begin to leak water. When a crack does not appear to be structural related, I have always recommended polyurethane. As a result of contact with water, polyurethane can expand anywhere from six to 30 times its initial volume (expansion rate depends on the manufacturer and the type of polyurethane). The result of the expansion makes the injection process more user-friendly for the applicator – as the urethane expands, the foam essentially fills any void areas inside the foundation. On the other hand, epoxy generally takes significantly more material than urethane to repair the same crack because epoxy does not have the same expansion capability.
The use of epoxy is necessary for related structural cracks in the foundation. With the injection of epoxy, the repaired crack essentially becomes significantly stronger than the surrounding area – the added strength of epoxy becomes vital for such repairs. Pending the severity of the structural problem, additional reinforcement products may be necessary to ensure that further movement or settling does not create additional cracks around the repaired crack.
Before one commits to a foundation repair using crack injection, the applicator should consult with a credible supplier to ensure familiarity with appropriate curing times of materials and correct use of all components. For example, when purchasing a two-part component, epoxy or polyurethane, its viscosity will determine which size mixing nozzle will best accommodate the injection of material. In addition, the capability of the materials reacting properly is critical – does the supplier guarantee that materials meet manufacturer specifications? Finally, a supplier (either a distributor or a manufacturer) should be openly available and honest to ensure that the contractor best serves his customers.
The crack injection has been used by waterproofing and foundation repair professionals for more than 20 years. It has proved to be a highly efficient and low-cost solution for homeowners while providing contractors a viable business endeavor. But, unfortunately, not all things in life are too good to be true.