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Old 10-23-2015, 09:01 AM   #1
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spray foam option


Hello, I'm in the process of researching spray foam options for my attic roof down to soffits, enlcosing/sealing making a conditioned space. I was just wondering if anyone here has spray foam in their attic particularly between joist of roof line. If so, are the any moisture problems regarding roof sheathing? Two types: open cell and closed cell spray foam, it appears that closed cell is the way to go due to vapor retarder. My house is old (1915). Thanks for any info.
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Old 10-23-2015, 09:21 AM   #2
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Where is the home located and what the reasoning behind encapsulating the attic?
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Old 10-23-2015, 09:32 AM   #3
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Quote:
Originally Posted by Windows on Wash View Post
Where is the home located and what the reasoning behind encapsulating the attic?
Located in PA. Looking to make it a finished space. 1-it has soffit vents and REALLY old batt insulation (falling apart) with an air gap behind it and then roof. So right now it's a vented attic. Furring strips currently hold up the insulation. My HVAC for upstairs is up there but everything is run around the perimeter including the air handler. The attic has good headroom and can easily be finished.2-I've read open cell spray foam can trap moisture in roof sheathing whereas closed cell does not. I was wondering if anyone has this in their attic.
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Old 10-23-2015, 07:43 PM   #4
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I have used Open Cell in quite a few insulated assemblies without issue. The building science will say to use CC SPF given its reduced vapor permeance.

I see no issue with either as long as the ceiling plane is airtight and well built.

You could incorporated a vented design with foam board and channels if you want to go that route as well.
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