Foundations are best repaired from the outside, we’ll excavate the area surrounding the crack. Once is’t been excavate, the crack is then chisled out 2 to 3 inches on each side and repaired with bonding agent and hydraulic cement. The bonding agent is important because it makes the old concrete adhere to the new. We clean and dry the wall thoroughly, then we put on a thick coat of foundation coating (tar) and wrap it with hydro guard which is a membrane that prevents hydrostatic pressure. While we are down there, we inspect the existing drain tile to ensure it has proper drainage.