Stemming seepage caused by the heaving of clay soil

Q. Water seeps into a room under a foundation wall in my 70-year-old home. The house is on a downslope and the room affected is 10 feet lower than ground level at the back of the house. Seepage water is needed to help swell the ground under the house. During the dry season, the doors bind; but in the rainy season they operate without sticking. Has the seepage damaged the walls? Two catch basins dug under a closet floor fill with 15 gallons of water after an inch or so of rain. Should I eliminate the basins and install ventilating fans? Should I drill holes into the ground so that the water will sink into the soil? Any ideas? James Lynch San Francisco

A. Your dwelling was obviously built on expansive soil. The clay condition accounts for the seasonal swelling and shrinking of the soil, which, in turn, moves the building and makes the doors fit or not fit.

If it were my house, I'd retain an experienced engineer or architect to inspect the problem firsthand and then follow the recommendations as to any remedial measures.

The problem sounds too serious to play around with.

The on-site inspection would determine the integrity of the existing foundation and whether or not it should be strengthened.

Our guess is that ventilating fans would be ineffective and a waste of money. Drilling any holes should be done only based on knowledge of the water problem and its control.

The engineer or architect may recommend tiling around the foundation walls so as to intercept the seepage and run it to "daylight."

Waterproofing of the interior concrete walls below grade may also be a recommendation. Use a sure-fire waterproofing agent such as Sealwall; made by the Sealwall Company of Eastlake, Ohio, or its equal. The Sealwall phone number is: (216) 951-3445.

Avoid experiments or guesswork by friendly amateurs.