crawl space vapor barrier


Old 12-04-13, 08:38 PM
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crawl space vapor barrier

Is it acceptable to use plastic across the floor joyce in the crawl space as a vapor barrier? I'm in the process of putting 6mm plastic on the floor of crawl space ,next I was going to use fiberglass insulation between the floor joist (the kind that is incased in plastic from lowes). A layer of plastic stapled to the joist would help keep moisture off of insulation and reduce drafts.
It is a vented crawl space.

thanks in advance,
Old 12-05-13, 06:13 AM
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Hi pbr,
Covering the floor area is good, but ventilating a crawl space in a hot humid climate concerns me. Inviting warm humid air into a cooler crawlspace seems to be inviting more moisture, which is what the VB on the floor is trying to eliminate. Instead of insulating and sealing off the crawl ceiling to isolate that space from the house, consider closing off the vents and insulating the foundation. Articles available if needed.

Old 12-12-13, 10:56 AM
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Thanks Bud , I have studied that a bit and I'm sure that's the smart way to go. However
with all my current projects there is not enough time or money right now to go that route.
I do live in the south where high humidity is the norm , but I'll have to wait to tackle that
One more question for you Bud, what kind of tape or glue (adhesive) should I use to
seal the 6mil plastic VB to the foundation walls?

thanks, pbr
Old 12-12-13, 02:04 PM
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Acoustical caulking works well.

You want something that is not incompatible with the plastic.

Be sure to seal all the seams and seal around any piers or penetrations is the vapor barrier.

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