Subfloor for Carpet (Slab on Grade)


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Old 10-28-17, 08:37 AM
J
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Subfloor for Carpet (Slab on Grade)

Hi All
New to the site but I was just curious, as I have been doing research, what I need (if anything) for a moisture barrier/subfloor under carpet on concrete slab.

I have a single level slab on grade home that I just bought. I am installing carpet in the bedroom (over concrete), pergo in the living room (over existing tile) and keeping the tile in the kitchen and bathroom. The house tends to have a damp feeling/smell to it that I have noticed. I was originally just going to lay the carpet over the concrete in the bedroom, but now am considering some sort of a vapor barrier potentially to help the dampness.

Can anyone recommend anything or if I need anything at all? I do not want to block the moisture just to have it saturate somewhere else in the house or slab. I also do not have alot of room to work with in terms of raising the floor (driLock probably would not work - too high).

Let me know your thoughts! they are much appreciated.
 
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Old 10-28-17, 12:49 PM
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Do a moisture test on the slab. Take a plastic garbage bag and using duct tape, lay it flat on the floor and tape it off. Wait a day or two and lift the plastic and see if moisture has condensed on the underside of the bag or if the slab is discolored from moisture. You then need to check to make sure your downspouts are adequately carrying the water away from the slab.

Usually carpet is just put on pad over the concrete. Your pergo/laminate will need a moisture barrier. even if it has the pad already attache to the planks. Laminate and moisture don't mix well.

First step is finding out if your place does or does not have a moisture problem.

Welcome to the forums, glad to have you here.
 
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Old 10-28-17, 01:36 PM
J
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Almost none of what you suggested sounds like a great plan.
If it smells moldy there's moisture issues someplace that need to be addressed.
Post some pictures of the outside of the home please so we can see what your seeing.
Just some of the many issues that can be found in a slab foundation.
Slab poured to low to grade, grade does not run away from the slab, mulch piled up against the outside of the home, no gutters, pluged up gutters, downspouts not far enough away from the foundation, no drain tile on the outside.
 
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Old 10-29-17, 08:04 AM
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Carpet will let much of the water vapor dissipate. If you put plastic under it, the water cannot dissipate and can grow mold.
 
 

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