Control Basement Moisture

The Basics

Water in a basement can be caused by something as simple as clogged downspouts to a more complicated scenario, such as a rising water table. Fortunately, most cures for wet basements aren't costly. Here's a look at the possible problems and solutions.

Condensation or Leaks?
When warm air comes in contact with cool basement walls and floors as well as plumbing pipes, condensation can occur. If water problems seem to clear up in summer when windows and doors are closed and the air-conditioner is running, condensation could be the culprit. Water collecting on the floor or dampness on walls or pipes isn't always condensation, however, but could be signs of leaks or seepage. To determine the source of the water, tape squares of aluminum foil to different spots on the basement floor and walls, using duct tapes to secure the edges. Leave the foil in place for several days. Droplets collecting on the underside of the foil indicate water seeping in from outside; droplets atop the foil point to condensation.

Excess humidity—which can be elevated by such internal sources as a basement shower, washing machine, or unvented dryer—can lead to damp walls, dripping pipes, and surfaces covered in mildew. To alleviate this condensation, improve ventilation in the basement by installing ventilating fans or opening windows during mild weather. You can also seal interior walls, add a subfloor system, and install a dehumidifier.

If condensation is forming on pipes, cover them with adhesive-backed insulating tape or foam sleeve insulation—both are affordable solutions and available at home improvement stores.