Musty odors coming from the basement or crawlspace are not only extremely unpleasant but can be both dangerous and expensive to correct if left untreated.
Excess moisture is the most common problem in basements and crawlspaces - either coming from outside or produced inside the home by everyday activities. Some studies show that as much as 50 percent of the air in a home comes from the basement or crawlspace. This can contribute to poor indoor air quality and cause uncomfortably high humidity levels. It may lead to costly problems such as cupping of hardwood floors, mold growth, increased air conditioner loads and swelling of millwork and cabinetry.
If you store anything of value in your basement or if you use your basement as living space, it is especially important to keep the moisture levels low. Relative humidity levels rising above 50 percent stimulate the growth of mold, mildew, bacteria and other biological allergens, which generate musty odors and can aggravate allergies.
Stop Moisture at the Source
Moisture often migrates into basements from the surrounding soil, and can be reduced by installing better drainage around the home, applying a water-resistant coating to walls and a sealer to a concrete slab floor, and increasing ventilation and temperature.
Dehumidifiers Can Help
Several organizations, including the Environmental Protection Agency, American Lung Association and American Medical Association, recommend using dehumidifiers - large-capacity portable models or central units - to maintain proper humidity levels in the home.
If you have a damp home or basement, dehumidifiers can help maintain the structural integrity of your home, inhibit mold growth and improve indoor air quality by removing odor-causing moisture. Some also filter the air, capturing mold spores and allergens.
Units should be connected to a drain or emptied frequently, because standing water in their reservoirs can actually grow mold.