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Do It Yourself: Condensation has quick, not-so-quick solutions

Q. Recently I noted several puddles of water on my concrete basement floor. Then I noticed there were beads of water on several cold water pipes and some of the water was dripping to the floor. I dried the pipes with a towel but soon after noticed they were again dripping. What causes this and can I fix it?

A. This is typical basement condensation caused by a high volume of water vapor in the air. The vapor is condensing on cold surfaces, which are often cold-water pipes, but can also be walls, floors, or any other surface that gets cold enough to act as a dehumidifier.

Very high humidity like this in a basement can be troublesome, since it can cause mold and mildew to form or, in extreme cases, affect structural parts by fostering rot or rust. The causes can be basement laundry equipment, improperly vented gas water heaters or central heaters, or moisture seepage through walls and floors.

The simple solution, which is not the best, is to buy some foam pipe insulation at a home center. This insulation generally comes in three-foot lengths and is available in several sizes to fit different sizes of pipes. The insulation has an open side seam that slips over the pipe. Insulating fittings like valves and elbows can be tricky, but the foam can usually be cut to fit and taped in place.

The best solution, however, is to make sure all basement appliances are properly vented and, if wall seepage is suspected, apply a waterproofing paint like Drylok. In addition, you probably need a good dehumidifier. Try to find one that will work at fairly low temperatures.

If you have a floor drain, the dehumidifier can be rigged to drain directly into it. If there is no convenient drain, the dehumidifier should automatically shut off when its tank is full and stay off until the tank is emptied and replaced.

Q. What could have caused the vinyl siding on one wall of an abandoned house next door to become warped and ripped? It appears to have melted. I assume that direct sunlight did this, but would like your opinion. Any ideas?

A. The average melting point of vinyl siding is 165 degrees, and the low point for melting is about 145 degrees – temperatures not normally reached by direct sun.

I think it is quite possible the siding damage was caused by a fire or vandalism.

However, there are rare cases where heat destruction to vinyl siding is caused by reflected, concentrated sun – sometimes by energy-efficient windows that have achieved a slightly concave shape and deliver focused heat.

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