I just ripped up my 30 year old basement carpet. There was significant efflorescence on the floor along along an exterior wall, where carpet padding wasn't used. The carpet in general felt "sweaty" and the underside had moisture stains in a few spots. Finally, sections of the floor with older concrete looked wetter. There was no trace of standing water, though.

My inclination is to vacuum the efflorescence and let things dry out for a week or so before laying down new padding and carpet with the plan to repeat in 5 years or so. Is there any other prep work I can/should do?

bare floor water stain
close up of concrete

1 Answer 1


Other than Avoid Carpeting In Basement (my policy, clearly not yours) I would certainly attempt some form of concrete sealant/barrier at minimum, since you evidently have moisture issues.

Preferable (but more expense now, against possibly longer service life for the new carpet) would be going to a product that elevates a new subfloor just a bit off the basement floor with space to dry below (basement subfloor systems with raised bumps on the bottom to create an airspace, not involving actual framing and greater loss of headroom) e.g (not associated with any) Dricore, Platon, DMX, Tyroc, Barricade, Amdry and probably others I haven't found. I'm specifically NOT pointing at one, because if you are aware of the products in general, you may find one not listed, or less expensive, made more locally to you, etc.

  • Regarding carpet: I've been told synthetic carpet paired with a dehumidifier is actually the best option for keeping the slab dry since the carpet will breathe. (I just purchased this house and the previous owner did not use a dehumidifier.) I was specifically advised against "water proof" surfaces like vinyl, as they will just trap water between the floor and the slab. I've read similar criticisms of barriers. I guess at the end of the day, there is no perfect solution and hence lots of conflicting recommendations. Sigh.
    – user169686
    Sep 10, 2023 at 15:33
  • Yeah, vinyl (without a dry-floor product to permit breathing) isn't great, either. Paint in the functional basement, tile in the nice part would be my approach, FWIW. If you can seal the surface of the concrete itself, that reduces the water coming in and needing to be removed. That's not the same as water trapped between the surface and sheet vinyl.
    – Ecnerwal
    Sep 10, 2023 at 15:46

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