Drying Out a Basement

House Doctor | Gary Dymski

June 21, 2001

Q. I have a problem in my basement. When there is heavy, constant rain, water leaks in by the chimney. Over time, this has not only ruined the carpeting but has caused the old vinyl floor tiles to loosen. Underneath the tiles is a sandy residue over what looks like tar. This surface is hard but everything is unsightly. The house is 50 years old.

It's been suggested we get a "skim coat" of concrete over the floor. Do we need to take up all the old tiles first? Can we put down new tiles where the old ones have come up and seam the new to the old with a patching compound? What can we do to minimize the water by the chimney, short of ripping down the knotty pine wood paneling and ripping up our outside deck? What is the best "skim coat" procedure, and can a homeowner do it?

-Mike Rizzo, Bayside, Queens

A. You've got quite a bit going on, Mike. First, I'd want to find out about the leak. Since it occurs only when there's heavy rain, I suspect the chimney. When's the last time you had it inspected by a mason? Make your own visual inspection: Look for cracked mortar joints, broken bricks, a brittle crown (the smooth concrete layer that covers the top of the chimney) or a missing flashing (the metal pieces that fit where the chimney meets the roof). Also, do you have a chimney cap? This cap, usually made of galvanized steel, is anchored to the top of the chimney and prevents rainwater and animals from going into the flue.

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Once you have stopped the leak, you can turn to the loose tiles. If they are as old and worn as you say, why not scrape them all off and install a new floor? Use a heavy-duty putty knife and a rubber mallet to chip away at the tiles. Be sure to wear goggles or safety glasses. To remove the tar-like material, try soaking small areas with mineral spirits. Let the mineral spirits soak in, then wipe up the residue with old rags. You also might be able to scrape it away with a putty knife.

Be sure to keep windows open and fans blowing when working with mineral spirits. The fumes can be a bit much.

As for a skim coat, if you find that your floor is reasonably level when you've removed all the tiles, why not cover it with a laminate floor? It's a great idea for stylish basement flooring and is simple to install.