The dry basement: what it takes to deal with dampness downstairs or in a crawl space.(Cover Story)

Water doesn't always know its place. It may show up in your basement or crawl space during a rainstorm or a winter thaw--or, for that matter, anytime it likes if your house and yard weren't finished with proper regard for drainage or the water table.

Too much moisture can be merely annoying, making the space below ground feel clammy, or it can be costly and dangerous. Large amounts of water can cause structural damage to the foundation and supporting columns and can promote the growth of health-threatening mold on walls.

Fixing a chronic moisture problem can cost as little as $140 for a good dehumidifier, or thousands of dollars for excavation, repair, and reconstruction. Severe water problems may require elaborate and expensive measures.

The illustrations below describe the most common problems, what you can fix yourself, and when it's best to hire a professional. The advice comes from our own experts and from Steve Andras, president of the National Association of Waterproofing and Structural Repair Contractors.

GETTING SOUND ESTIMATES

Andras' trade association, at www.nawsrc.org, can direct you to association members in your region. You can find other good leads to qualified local contractors at www.improvenet.com. You can also ask for recommendations from friends and relatives who have successfully repaired a below-ground space.

As with any major home repair, get comparable bids from at least three contractors and come to terms in writing before you agree to the work or part with any money.