Basement foundation crack repair, sealed in one visit.

Polyurethane or epoxy: which crack gets which?

Both are injected from inside through small ports set along the crack, and both fill it through the full thickness of the wall. The difference is what they do once they're in.

Typical Hamilton-area ranges before tax. Long cracks, several cracks and finished walls change the price.

Which cracks injection fixes, and which it doesn't

Injection is made for solid poured concrete walls. Vertical and diagonal cracks in poured walls are the classic case: they're usually shrinkage cracks that formed as the concrete cured, and they leak when the ground outside is wet.

• Good fit: a vertical or diagonal crack in a poured wall that leaks in the spring or after heavy rain.
• Needs a structural look first: a horizontal crack, a crack wider than about a quarter inch, or one side of the crack sitting proud of the other.
• Different fix entirely: block and stone foundations. They leak through joints and hollow cores, not a single clean crack, so they need block, stone or drainage repairs instead.

Not sure which you have? Text us a photo and we'll usually tell you before anyone comes out. For the full rundown, read when a crack in your basement wall is a problem.

Why cracks leak in the spring

Soil around a foundation holds water. When it's saturated, in the spring thaw or after a big storm, that water pushes against the wall and finds the easiest way in, which is any crack. That's why a crack can stay dry all summer and run every April. Sealing it through the full wall thickness, rather than patching the surface, is what stops it for good.