No Insulation In Crawl Space Under SubFloor

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Small Cabin Forum / Cabin Construction / No Insulation In Crawl Space Under SubFloor

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# Posted: 30 Jul 2022 21:52
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I recently remarried and my spouse has a cabin near West Yellowstone. Thereâ€™s a crawl space under her sub floor. I see spray foam insulation where the cement foundation is around the outside. However, thereâ€™s no insulation under the sub floor and the tile is freezing most of the year.

Is it common to not insulate under the sub floor? The crawl space is about 5â€™ high. The joist are 16â€ on center and thinking I should install insulation bats or spray foam. Thoughts?

Brettny
Member

# Posted: 31 Jul 2022 07:16
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Is there plumbing under there?

Nobadays
Member

# Posted: 31 Jul 2022 09:01
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We spray foamed under the floors first and it made a big difference in comfort level. Both for cold floors and overall cabin warmth. Last fall we had the perimeter sprayed and this kept the crawlspace above freezing all winter.

If it makes a difference... We have plumbing under the cabin but it is wrapped with foam insulation and was not sprayed.

RetiredAt49
Member

# Posted: 31 Jul 2022 10:09
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We do have plumbing under there (in crawl space) but we have a space heater in there during the winter.

RetiredAt49
Member

# Posted: 31 Jul 2022 11:30
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Attached are some photos

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gcrank1
Member

# Posted: 31 Jul 2022 12:56
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Wouldnt heat tape on the pipes be more energy efficient than heating the whole space with that heater?

The Grand Pooh Bah
Member

# Posted: 31 Jul 2022 14:18 - Edited by: The Grand Pooh Bah
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I would insulate the floor. I have 2 x 12 floor joist and R-30 in my floors. They never get cold in the winter.

RetiredAt49
Member

# Posted: 31 Jul 2022 17:49
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I want to insulate the floorâ€¦ what Iâ€™d like to know is what would you recommend? Bats? Spray foam? Iâ€™m thinking bats would be a problem if animals make nestsâ€¦. But it would be cheaper than spray foam

spencerin
Member

# Posted: 31 Jul 2022 22:47
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Spray foam would be best, if price isn't a concern. I would avoid bats for the reason you stated, as well the fact that they can absorb moisture. If you don't want to pay for spray foam, then I would do foam board.

No, it's not uncommon to not insulate the subfloor if the perimeter of the crawlspace is already insulated.

Brettny
Member

# Posted: 1 Aug 2022 12:45
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Quoting: RetiredAt49

I want to insulate the floorâ€¦ what Iâ€™d like to know is what would you recommend? Bats? Spray foam? Iâ€™m thinking bats would be a problem if animals make nestsâ€¦. But it would be cheaper than spray foam

You alreaty have spray foam on the walls. Do you close up the vents in the winter?

Why not just spray foam the floor? It can be done right over gravel or concrete. This would make any future leaks, repairs or adjustments needed easier. It will also allow for a heated envelope for your pipes.