Condensation and improperly installed or malfunctioning drainage systems are common causes of dampness in the basement. Poor ventilation, improperly sized air conditioning units, leaking air vents and dirt floors in the basement also cause moisture problems. Leaks from water pipes can lead to excessive moisture in the basement.
To direct water away from the home, install gutters and downspouts, and clean the gutters regularly to ensure water is draining properly. Install vents in bathrooms, on clothes dryers and above cooking appliances to reduce indoor humidity levels.
Grading, or sloping the ground slightly away from the home, prevents ground water from entering the basement. Leaking air ducts or an improperly sized air conditioning unit leads to excess moisture in the home, and a dirt floor in the basement naturally emits water vapor. Have air conditioning units inspected and repaired if necessary, and seal dirt floors with plastic to prevent dampness.
Excessive rain can cause the water table in the region to rise, resulting in saturated soil around the basement. Install drain tile systems to prevent humidity caused by saturated soil, and repair water leaks immediately. If a sump pump is present, check its operation to ensure it is working properly. Place a dehumidifier in the basement if dampness persists.