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What R-Factor should I consider use when insulation our crawlspace?

The floor under our new crawlspace was not insulated. The space between the floor joists is about 15 inches and the depth seems to be at least 12. The crawlspace is partially exposed concrete from the old patio and gravel over part of the original back yard. The space height of the crawlspace is roughly 4 feet. And the foundation wall was insulated with R19 insulation. Do we use the same between the floor joists?

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1 Answer from this member:
Manage My Life
The more insulation the better. There should be a vapor barrier on the warm (floor side) of the insulation, or else you can run into condensation problems if warm moist air from your house moves out through the floor area.

You should also protect the insulation from damage (mice, insects) from below. A layer of 3/16" chipboard is a good barrier, and will also stop the insulation from falling out.

You might want to consider having a contractor install foam insulation. This would provide superior insulation and air sealing, as opposed to fiberglass or mineral wool batts.
by Manage My Life
November 13th, 2008
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