Interior footing drains made of perforated pipe
Illustration: Tom Moore
For sever seepage: Interior footing drains made of perforated pipe set in gravel carry water to a sump pump, which pumps it out of the basement.
Subsurface Sources

If your wet-basement symptoms act like runoff but occur all the time, you're probably dealing with high groundwater.

Diagnosis. Unless the foundation is surrounded by soil that has a high clay content, which can hold rainwater and snowmelt for months, runoff problems usually come and go as storm water drains away. But if your basement is consistently wet long after a storm, or if water is flowing through your walls or bubbling up where the walls meet the floor, you probably have a subsurface water problem. Check with your city or town to see if the water table is unusually high in your area or if underground springs are common.

Curing it. You may want to call a pro for these problems. Solutions range from the relatively simple (injecting absorbent clay into the soil and urethane caulk into cracks, $500 and up) to the more involved (creating a sump and installing a sump pump, which costs about $300 to $700).

A contractor may also suggest combining a sump pump with perimeter drains made of 4-in. perforated PVC drainpipe laid in gravel inside foundation footings. These interior systems, which channel away water before it enters, require extensive jackhammering and roughly cost $3,000 to $5,000. Exterior systems, which run at the base of footings, are even more complicated; they require removing the landscaping, excavating to expose the foundation, covering it with a waterproof membrane and laying perimeter footing drains in a bed of gravel. This can easily cost up to $10,000.

Considering the high cost of quelling subsurface water, doing it right is crucial.

• Be sure the contractor is insured and offers guaranteed work.

• Get a firm or not-to-exceed price with detailed specifications.

• Ask three past clients the following: Would you use the contractor again? Did he solve the problem? And, did he respond promptly to callbacks?
Ask TOH users about Basements & Foundations

Contribute to This Story Below

    More in Basements & Foundations