Q: I have a few cracks in a 35-year-old concrete perimeter foundation. Is there a product that can be squeezed into these cracks to strengthen the foundation and avoid problems?
A: If the cracks are not excessively leaking water into the basement, leave them alone. If they are wide enough to take mortar, you can fill them as part of an autumn project that will put hair on your chest. It’s hard work. If some floors are sloping a bit, keep an eye on the foundation to make sure the concrete stays put.
Q:Our 1860s house has a stone foundation. About 10 years ago, a concrete-slab floor was added and a sump pump was installed, but the basement still feels damp. Will a dehumidifier help? Most people seem to think they’re a good way to reduce moisture in damp basements, but a few say they worsen the situation by "making the walls wick up even more water." What’s your opinion? CURIOUS, in Cambridge
A: Dehumidifiers work very well, but often too well, sucking water vapor up through the slab even after the basement air is nice and dry. That is what you read, and it is good information. Open all windows for cross ventilation and keep them open as long as they are forcing damp air outdoors. It’s too bad they didn’t put a polyethylene vapor barrier under the slab when they poured it. That would have helped a lot.
The Boston Globe