Musty Basements Could Be a Sign of Mold

Musty odors in basements can be caused by water vapor entering through the concrete walls and floor from moist soil around the basement.  A moist basement wall may be due to moisture in the air condensing when it touches the cool wall surface.   

      The first step is to check to make sure your home has proper drainage to avoid water vaporizing in the home. When building your home, or making improvements, here is the best way to avoid moisture build-up in basements. Install at least 6 inches of gravel underneath the basement concrete floor. This forms a water drainage layer and radon removal layer. Place a vapor retarder between the concrete floor and the granular layer to minimize radon and moisture entry into the house.  Place 4-inch drainage pipe along both the inside and outside of the concrete footing. The top of the drainage pipe should be below the top of the footing. Install a coarse gravel envelope around the drainage pipe.   

       Next, place filter fabric around the coarse gravel to prevent soil particles from clogging the coarse gravel. Put gravel or a drainage mat next to the concrete foundation wall (basement wall) to allow water to drain into the drainage pipe and to keep wet soil away from the wall.   

       Then, place a layer of low permeability soil, such as clay, near the surface to limit the amount of water soaking into the ground next to the wall. Slope the ground about 1 inch per foot away from the house. Extend down spouts several feet away from the house. One inch of rain on a 1,000 square foot roof is equal to about 625 gallons of water, which isn’t something you want next to your basement.