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sdavisnh
Vapor barrier for flooring

I have just put a 4-season sun room over a concrete pad. I used 2 x 6 directly on the pad and extended it about 2' beyond into gravel/dirt. It has 5/8 decking on top and is insulated with 2 layers of 2' foam board underneath. I am using Allure vinyl flooring ...my question is, should I use a thin foam underlayment underneath the flooring ? I don't think any moisture will be a problem but wanted to check.

dj1
Re: Vapor barrier for flooring

can you upload pics?

Upload your pics in a host like photobucket, then tell us where to find them.

Mastercarpentry
Re: Vapor barrier for flooring
sdavisnh wrote:

I have just put a 4-season sun room over a concrete pad. I used 2 x 6 directly on the pad and extended it about 2' beyond into gravel/dirt. It has 5/8 decking on top and is insulated with 2 layers of 2' foam board underneath. I am using Allure vinyl flooring ...my question is, should I use a thin foam underlayment underneath the flooring ? I don't think any moisture will be a problem but wanted to check.

As you describe it, it seems that the bottom is open to the exterior. This is not a great idea for a number of reasons- pests can get under there as can moisture plus there's air infiltration too. Fix that first, perhaps extending the concrete under that by adding a new pad. 2" twice does not equal the 5 1/2" of a nominal 2X6 so the rigid foam needs something on top of it to be effective. Based on my understanding of your post, it seems that you're well past easily correcting these issues unless you remove the 5/8" subfloor to gain access. I hope I'm wrong.

As to the Allure flooring, always follow the manufacturer's instructions which can almost always be found 0nline if they do not come with the material. Doing anything else voids any warranties and may cause premature wear or failure.

Phil

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