I have a lot of clients ask me if they need to excavate the exterior of their foundation when they are using cocrete epoxy to mend a cracked wall. The answer is yes and no. In theory, by exposing (and then sealing) both sides of the crack, you can guarantee that a wall is 100% sealed and bonded. The reality is that often, it is not practical to excavate, hence we have “blind sided crack repair”. This involves sealing the inner edge of the wall while mounting injection ports every 12-24″. If there is considerable weight outside the wall, the epoxy should fill the void (the crack) and not waste into the soil. After seeing numerous foundations excavated that had already had epoxy injection, we know that the soil works fairly well as a sealant. Usually 15-25% of epoxy used will exceed the dirt side of the wall which is considerably cheaper than excavation. Foundation repairs using concrete epoxy can cost as little as $150 and can exceed $1000 for a major crack repair or rebuild. We have been installing commercial epoxy in Denver, Boulder, Littleton, Highlands Ranch and Aurora for years. It works but only if installed by someone with the experience to deal with each challenge that wall repair brings.