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Basement Carpet Underlayment

How to prevent moisture when carpeting a concrete basement floor with baseboard heating

guys on stairs

I plan on carpeting a concrete basement floor with baseboard heating in northern New York. I can go up about an inch and a half without modifying the heating. What should I use under the carpet to prevent moisture and provide maximum insulation?

— William, Brookfield, Connecticut


Steve says: The first question to ask is, does your slab have a vapor barrier underneath? One way to test for that is to tape a piece of plastic, say 12x12, to the floor and leave it there for 24 to 48 hours. If it's got condensation on it after that time then you can reasonably assume that the slab was not installed with a moisture barrier, and you're going to have to provide one. What we did in Charlestown was to put down an underlayment that is a cellulose-based soundboard, which also works well as a substrate for carpet and insulator. That's about 3/4-of-an-inch, and then you've got the carpet pad, and then the carpet. So I think you should be able to get all that in without having to modify the heating.


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