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SPF in a damp crawl space?

Jazguy's picture

SPF in a damp crawl space? (post #202136)

Jazguy on Sun, 05/22/2011 - 10:43 (updated 05/22/11 - 05:16) 
in

I have house built in '52 on expansive soil. The crawl space soil stays damp year round. I have plastic sheeting on the soil; it is not sealed to the foundation. Standard crawl space vents. There is no insulation under the house.

I was thinking that it would be easiest to insulate and air seal the house with spray foam insulation. I am not sure if that is wise with the amount of moisture that is under the house. Will the SPF collect moisture or allow it to be trapped in the subfloor?


Anyone have any thoughts or experience?

-A +A

Closed cell (post #202136, reply #1 of 4)

by davidmeiland in reply to Jazguy [original] on Sun, 05/22/2011 - 12:13

foam is highly impermeable and will not permit additional moisture through. If there is a lot of moisture in your subfloor or joists, and it can't dry to the top, I would dry it out before foaming it. And I would seal the vapor barrier sheet well at all overlaps and at the perimeter.

You should get ahold of a moisture meter and take some readings in the framing and subfloor materials.

I would use the (post #202136, reply #2 of 4)

by Raymond Morton in reply to Jazguy [original] on Tue, 05/24/2011 - 15:45

I would use the spray foam insulation as well and definitely dry everything out first.  Just make sure if there are any large gaps in the floor boards that the foam will not go through to the other side, could make quite a mess.  If you want more information go to http://www.sprayfoamdirect.com/

Would you recommend closed (post #202136, reply #4 of 4)

by sallyspf in reply to Raymond Morton [original] on Mon, 01/09/2012 - 08:00

Would you recommend closed cell foam or open cell?

Thanks. Sounds like a plan. (post #202136, reply #3 of 4)

by Jazguy in reply to Jazguy [original] on Fri, 05/27/2011 - 10:23

Thanks. Sounds like a plan.