Basement moisture is a common problem, but you can manage it on your own, and it shouldn't be ignored. High moisture levels in the basement of a home can cause mold and mildew growth, which sometimes lead to health problems. Controlling moisture in the basement is especially important if you plan to finish your basement or install carpets, furniture and other items that are susceptible to mold.
Signs of a basement moisture problem include damp or humid air, visible mold, the musty odor of mold, standing water on the floor and the rotting or decay of wood or carpet. Basement moisture can have several causes, including condensation, improperly vented appliances, foundations that are improperly graded and allow water to settle near the house, gutters or downspouts that don't work properly and cracks in the foundation.
If you have moisture problems in your basement, first remove any obvious sources of moisture, such as humidifiers or stoves. Make sure bathrooms, clothes dryers and other appliances vent to the outside of your house, not to your basement. Do not ventilate the house with humid outside air. For example, opening basement windows in the summer may cause condensation indoors.
Next, examine your outdoor sources of moisture, such as the grading of your foundation and your gutters and downspouts. Fix any obvious problems. For example, if your gutters don't have downspouts, install downspouts to help rain drain away from the house. In addition, seal any cracks or air leaks in the basement.
If you still have moisture problems, consider installing an exterior drainage system. This requires you to rebuild the area near the foundation, which can be expensive. However, exterior drainage systems usually eliminate moisture problems. Don't rely on a dehumidifier to permanently solve severe moisture problems. Drying out the basement air can actually cause wet air to be drawn in to the basement, which leads to structural damage.