Vapor Barrier Between Subflooring and Finish Wood Floor
GROUNDUP
| Posted in General Questions on
Hello. I am doing engineered wood floors over advantech subfloors. Is there supposed to be a vapor barrier between the subfloor and wood floors?
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Replies
Of course, the best advice will be found in the installation instruction for the flooring you have chosen.
I like to see something like a layer of tar paper under the floor if allowed in the instructions I feel you are less likely to have squeaks with the paper.
What is below the Advantech could shape my choice also.
Walta
groundtogreen,
You are fine without a vapour-barrier under your flooring.
If there is a difference in the humidity levels between the room the flooring is going into and the space below, that humidity problem needs addressing. Or if the floor is over unconditioned space, the floor assembly needs to be designed to stop vapour movement.
Engineered floors usually don't need underlays the way solid wood ones do, and if they are required they are for comfort, or acoustical separation.
If you ever install wood floors, don't use tar paper - it smells. Use rosin paper which is designed as an underlay.
Thanks so much. It's over the basement but I do have controlled humidity there and it's conditioned.
Long ago they used "building felt" (Asphaltic impregnated paper, commonly known as "tar paper") under wood floors. The installers still use that term, but the actual material most currently use is a synthetic material that has no asphalt or tar in it (similar situation over roof decking under shingles). HOWEVER, it is always best to confirm and determine and agree upon the exact material in advance.
That said, I am wondering if there are any issues with installing a vapor barrier material over the subfloor/under the wood floor when the space below is conditioned.
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