If you’re struggling with a damp basement, you may be tempted to “solve” the problem by painting your basement walls with a waterproof coating that promises to keep your walls dry. Don’t do it! Not only do these waterproof coatings fail to deal with the underlying causes of basement moisture, they often cause problems of their own.

Before you try to eliminate basement moisture, you need to determine its source. The easiest way to do this is to tape a square of plastic (a piece cut from a garbage bag will work) securely to the inside of your basement wall. Wait a few days, and then check to see if moisture has collected on the surface. If the “room side” of the plastic is damp, the moisture has condensed out of the air onto the wall surface. (Since basement walls are underground, they are cooler than the other walls in your house.) Such condensation is a frequent occurrence in summer, when the humidity is higher. Painting the wall will not solve this problem; you’ll need to run a dehumidifier or open more windows to increase air movement.

If you find moisture underneath the plastic, on the “wall side,” you’ll know that it’s exterior moisture that has come through the wall or the floor. The most effective way to deal with this problem is by diverting the water before it collects alongside the wall and starts to move through it. (Read more….)