So you woke up one morning and noticed that you had a tiny crack in your basement wall. Not a big deal, it’s not really letting any water in and it’s not long enough to worry about full-on basement waterproofing or mold removal measures yet, right? Well, no. Quite wrong, actually — you should worry about any crack in your basement wall. Repair on the inside surface might seem like overkill, but that same crack might be feet long on the outside edge of the wall.
Particularly if you live in an area that has lots of clay (or benonite) in your soil, the pressures that can cause a small little crack on the inside of your wall can easily be causing a much larger and nastier crack on the outside. Basement waterproofing experts in your area will generally be able to tell how much of a concern that kind of thing should actually be, but the point is that you need to call those experts right away.
Because it’s probably larger on the outside, even a small-looking crack can eventually lead to standing water. In basement wall repair, the outside edge of the wall almost always needs to be examined — which means digging up the area next to your house and making a thorough visualinspection. You could risk just getting a basic basement sealing and hoping that fixes it, but it’s a gamble; you might well end up doing it again within the year, and having more serious issues to deal with, like mold remediation.
That little tiny crack is the result of some very powerful forces — hydrostatic pressure from water building up in the soil outside of your home, geostatic pressure from the clay swelling as it heats and absorbs water from the dirt around it, and of course it’s own expansion and contraction as the temperature of the wall itself changes over the seasons. The combination can easily turn that tiny crack into a buckling wall within a year if it’s not tended to immediately.
The first step is to get the basement wall repaired. If the crack turns out to be small on both sides, an expanding polyurethane foam can be injected into both sides of the crack. The foam not only forms a waterproof barrier that seals the crack, but it holds the sides of the crack together and keeps it from spreading as easily. The low viscosity of the foam allows it to penetrate deep into a crack and do it’s job well. In some cases, the basement waterproofers will come back and add a layer of epoxy, which bonds with the concrete on either side to add strength and flexibility to the crack.
Anything more serious than that will require professional-grade tools and expertise, but they can all be filled in one way or another.