This post is from a suggested group
Polyurethane vs. Epoxy Injection for Leaking Basement Walls
We recently stripped back some wood paneling in our finished basement and discovered a diagonal crack running down the poured concrete wall with clear signs of past moisture entry. I have been researching repair options, but I am confused about when contractors use flexible polyurethane injection versus rigid epoxy injection. Which material is better for stopping groundwater leaks in Toronto foundation walls?

The right material depends on whether the crack is actively leaking water or serving as a structural tie. Polyurethane foam expands rapidly upon contact with moisture, filling the entire depth of the crack out to the exterior soil with a flexible seal that expands and contracts with thermal shifts. Epoxy, on the other hand, restores structural shear strength to dry, non-moving concrete. You can review crack repair methods and materials at https://leaquida.ca/interior-waterproofing-toronto/crack-repair/ A technician will inspect the crack's movement and moisture level to determine the correct injection compound.