Checking for Basement Moisture Sources

If you see evidence of excess moisture in your basement but aren’t sure about the source, here is simple test. Using duct tape, fasten pieces of heavy plastic or aluminum foil (about 20 inches square) to suspected damp areas of the walls and floor. Dry the area first.

Check the squares every few days. If you find moisture on top, that is a sign of condensation from high humidity in the room. Moisture on the bottom or inside indicates seepage through the masonry. Moisture on both sides means that you have to contend with sources both inside and outside the basement.