Wall cracks can become a source of seepage leading to mold growth and cause damage to your basement or building. Cracks can form from shrinkage, thermal stresses, movement, hydrostatic pressure and shifting or settling. It’s imperative to deal with cracks immediately and cease them from spreading in order to avoid further damage. The repair is typically done through the injection process of a hydrophobic polyurethane for moisture/seepage or an epoxy injection for structural purposes. Residential basement foundation wall crack injections are typically done with the hydrophobic polyurethane to prevent seepage where the urethane is a closed cell foam that can expand and contract. In contrast, epoxy crack injections are typically used in commercial applications or for structural purposes where the epoxy yields high strength.