We’re in the process of building an addition in San Francisco that is about 3′ below grade and we are putting carpet in the finished space.
The basement walls have been coated with Xypex, we have mirror drain on the outside of the foundation and a french drain installed around the perimeter to get rid of the water. The slab itself has a 10 mil plastic membrane below it. I.e. rock, membrane, sand then concrete.
We have had a lot of rain recently and there does not appear to be any moisture problems present, but I do not seem to be able to get a straight answer about what, if anything, should go on the concrete floor prior to the carpet.
I have been told, no to plywood, becuase it would warp and buckle if there were any moisture. I’m dubious about putting a non-permiable barrier down like Drylock because then it can’t breath at all. Someone had suggested a rubber mat, like Regepol that is often used also for sound proofing and others have just said lay the carpet with a good pad.
There seems to be a lot of conflicting information about barriers in basements at the moment, but all the discussion I’ve read has been about the walls, how about the floor?
Thanks
Replies
In the Midwest, where basements are ubiquitous, it's common practice to lay the pad directly over the concrete if it's a dry basement. I would hesitate to lay down any plastic or membrane on top of the concrete. Some water vapor will inevitably migrate out of the slab (unless you live in Phoenix), and I prefer to give it a way to naturally dissipate rather than trap it under poly (again, assuming that you have an otherwise dry basement).
Ok, I live in Seattle, have two separate basement areas with carpet, we've had over 23 days straight of rain (raining now) and both of these areas are doing fine. Our basement is separated into the original, higher level with the original thin slab (house built in 1908) and the lower level with a five-year old slab over 6-mil, over clay.
The upper basement as I'll call it has a french drain along the micro-footing (1908!) to a sump as this wall is against the higher grade so we had water problems before this side was finished....now for about two years it is covered with a felt pad and wool berber with no problems.
The lower side of the basement has that pink foam pad with a cut pile carpet. No problems.
I was concerned as well about the issue but just went for it after the water problems were solved.
Hope this helps.
If the basement was properly installed everything should be dry, so you just lay the carpet on the concrete.
Didn't someone recently (or maybe not so recently) come out with a TNG OSB product that has a rubber back side with a bunch of little rubber feet for exactly this purpose? I can't remember what it is called, but recall seeing it at the big orange box.
http://www.dricore.com/en/eindex.htm
Billy