Ask the Carpenter: What to do if you have a wet basement floor

Ask the Expert Home Improvement
. AP

Q. I have water leaking into my cellar. The water migrates through the foundation along with dirt, covering the floor. The water seems to enter about 2 feet above the cellar floor, which is below ground level. The area outside is paved with hot top. A neighbor seems to think that there is a hole in the ground outside and that is where the leak starts to migrate. I’m not sure who I need to call to take care of the problem. I have called several pavers, but none called back. The neighbor seems to think that the hot top should be removed to locate the hole. What should I do?


A. You most likely have a hole in your foundation. You didn’t say whether it is concrete block, poured concrete, or fieldstone. Make sure that the hot top is pitched away from the house and that the drain spouts direct water away from the house. If the spouts drain into a drywell, that could be the source of the problem. Inside the basement, look for cracks/holes in the foundation and seal them with hydraulic cement. Or, consider repointing if the foundation is fieldstone. If you don’t have gutters, get some.

Q. I have an old house with a stone foundation I had repointed a few years ago, but I still get moisture coming up through the slab. In some places, it is wet throughout the summer and into late fall. A mold remediation provider told me that I could cover the entire floor with 2 to 3 inches of concrete to prevent it, but I don’t think that solution would be feasible given the complexity and inconvenience. He also mentioned that he has successfully used a paintable coating product with a rubber-like quality. He didn’t remember the name of it. Are you familiar with such an application? If so, what do you think of it?

S.D., Cambridge

A. If water is coming through the slab, adding another 2 to 3 inches to that slab will not solve your problem. By wet, do you mean a puddle or just that it’s damp? Is the moisture due to a rising water table, a lack of gutters, or a poorly graded foundation? I do not recommend painting anything over the concrete if you have moisture problems. I have a fieldstone foundation that I repointed, and I get great results from using a dehumidifier year round, one that drains into a laundry-type sink. The dehumidifier keeps the air moisture down and the space too dry for mold growth. Try that first. It’s your least expensive solution.

Rob Robillard is a general contractor, carpenter, editor of, and principal of a carpentry and renovation business. Send your questions to or tweet them to @robertrobillard. Subscribe to our free real estate newsletter at