Basement slab moisture barrier
I am finishing our 800 sq.ft. basement in Portland, OR (zone 4c). I am planning to lay a combination of carpet and linoleum and want to reduce the chances of mold from moisture that might seep up through the concrete slab, which varies in thickness from 2″ – 4″ in some spots. I have noticed a couple 6″ diameter spots on the slab that seem moist during the rainy season, but no pooling of water. I have taken several steps to minimize moisture in the basement, including exterior grading of soil, exterior french drain as well as interior french drain for redundancy in spots that were problematic in the past. My concern is dealing with the small amount of moisture that is less obvious, yet can still cause mold.
I am wondering if I should consider any sort of moisture barrier between the concrete slab and the carpet / linoleum? I wondered if some sort of plastic tarping, rubber matting, or paint-on product might be helpful, or if it might create problems that I did not anticipate.
It is important to know that any product used to solve this potential problem will need to be thin, as overall height in the basement is a concern – appx. 6’4″.
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