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Tyvek for floor water vapor prevention under hardwood

johndrew's picture

I have a roll of Tyvek house wrap. Can I use that to go under hardwood flooring?

Thanks for your usual support.

For what purpose?  What's (post #207337, reply #1 of 6)

For what purpose?  What's under the floor?  What do you mean by "water vapor prevention"?

Tyvek is an air barrier.  It allows water vapor to penetrate, but tends to prevent the penetration liquid water.

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

What Dan said. Tyvek is (post #207337, reply #2 of 6)

What Dan said.

Tyvek is basically GoreTex for lets moisture through, by design. If you want to prevent moisture transferance then don't use it.

question.. (post #207337, reply #3 of 6)

What's under the floor to be floored? Basement, crawlspace or other?


Crawl space about 2-4 feet. (post #207337, reply #4 of 6)

Crawl space about 2-4 feet. What is the difference between tar paper and resin paper to go under the flooring?

Not much difference, John. (post #207337, reply #5 of 6)

Not much difference, John.  Neither tar paper or rosin paper are vapor barriers.  Tar paper resists liquid water pretty well.  They are often used under wood floors to supposedly resist squeaks.  I don't believe they do much to help that problem but they do no harm.  I recently read an article in another magazine where the author used Tyvek under the wood floor to create an air barrier.  It might make sense if you have a board-sheathed floor, but not if you have a sheet-stock floor--it's simpler and more effective to just tape the seams in the sheathing.

If moisture is your concern, (post #207337, reply #6 of 6)

If moisture is your concern, you would do well to cover the dirt of the crawl space with 6-mil plastic sheet. This will protect not only the flooring, but the framing as well.