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Charles Whittle Posted: May 30, 2008 02:29 PM	Open Cell or Closed Cell Open Cell OR Closed Cell Foam? I have a vented crawl space under a residence with a 2x6 tongue and grove floor. I get some movement in the floor that is causing problem with the filler between the boards. On occation the ground gets wet under the house and may take a month to dry. Shoud I use a open cell or closed cell foam? and why? Also is there anything else that I need to do before or after I spray the foam. The house is in the Gulf Coast area just north of Houston.
Colin Farrell Posted: May 30, 2008 02:40 PM	i'm gonna answer it all real quick and simple for you here since i'm sure you'll get tons of responses...but you answered the question yourself. if you want to keep moisture out you might not want to put a sponge (open cell foam) in place as a moisture barrier.
mason Posted: May 30, 2008 02:46 PM	FEMA has designated closed cell SPF as flood resistant insulation for these type of applications. So in this case I would go with the closed cell.
Charles Whittle Posted: May 30, 2008 02:51 PM	I don't have to worry about a flood or even the foam getting wet, it's the humidity that i would like to keep out. I think the humidity is what's causing the floor to move.
mason Posted: Jun 01, 2008 01:11 PM	Tongue and groove planking will expand and contract with absorption and drying out of water in the wood. It can also be affected by structural movement of the building (having nothing to do with humidity). Closed cell foam installed to the wood will not eliminate water vapor transfer or structural movement, but, it will slow the rate & the volume of water vapor transmitted into the wood, and it will tend to reduce some structural movement as well.

Author

Comments

Charles Whittle

Posted: May 30, 2008 02:29 PM

Open Cell or Closed Cell

Open Cell OR Closed Cell Foam?

I have a vented crawl space under a residence with a 2x6 tongue and grove floor. I get some movement in the floor that is causing problem with the filler between the boards. On occation the ground gets wet under the house and may take a month to dry. Shoud I use a open cell or closed cell foam? and why? Also is there anything else that I need to do before or after I spray the foam. The house is in the Gulf Coast area just north of Houston.

Colin Farrell

Posted: May 30, 2008 02:40 PM

i'm gonna answer it all real quick and simple for you here since i'm sure you'll get tons of responses...but you answered the question yourself. if you want to keep moisture out you might not want to put a sponge (open cell foam) in place as a moisture barrier.

mason

Posted: May 30, 2008 02:46 PM

FEMA has designated closed cell SPF as flood resistant insulation for these type of applications. So in this case I would go with the closed cell.

Charles Whittle

Posted: May 30, 2008 02:51 PM

I don't have to worry about a flood or even the foam getting wet, it's the humidity that i would like to keep out. I think the humidity is what's causing the floor to move.

mason

Posted: Jun 01, 2008 01:11 PM

Tongue and groove planking will expand and contract with absorption and drying out of water in the wood. It can also be affected by structural movement of the building (having nothing to do with humidity).

Closed cell foam installed to the wood will not eliminate water vapor transfer or structural movement, but, it will slow the rate & the volume of water vapor transmitted into the wood, and it will tend to reduce some structural movement as well.

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