Foam insulation in rafter cavities?


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Old 03-10-22, 02:26 PM
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Foam insulation in rafter cavities?

Sorry if I posted this twice - new member:OK, a bit of background on the structure in question; it's an off grid house with 2 x 12 open rafters. Roof is typical; plywood deck, felt paper, asphalt shingles - then overlaid with metal roofing. There is a wood burning stove inside, and I will be putting in a direct vent propane heater as well. But neither will be utilized frequently as this is a seasonal dwelling with no access during the winter months. Temps range from -30 in the winter to 90 in the summer. Very low humidity year round (9000 feet up in Colorado). No insulation in the ceiling at all, and that's what I want to add, and add economically cuz I ain't made of money.



So here's the question; would there be moisture issues if I were to push 2" thick painted rigid foam up into the rafter cavities, then simply hold them in place with perimeter quarter round? There is no air circulation in the cavities and I want to keep the rafters exposed.
 

Last edited by GunnisackJack; 03-10-22 at 03:03 PM. Reason: clarification
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Old 03-10-22, 02:27 PM
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They cant be left exposed, a fire hazard!
 
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Old 03-10-22, 02:29 PM
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Marq1 - not a concern - WAY off grid.
 
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Old 03-10-22, 02:46 PM
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I have never lived anywhere where exposed rafters were prohibited. However, exposed insulation is another matter. I think it needs to be covered even off grid. Foam insulation is highly toxic.

BTW We have friends that live in Colorado at 9000' (Evergreen) in a nice modern house. Their rafters are exposed under a built up roof. It's a great look.
 
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Old 03-10-22, 02:55 PM
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Thanks cwbuff. I am planning to paint the foam. This is by NO means a house that would find a place in Evergreen. It's really more of a cabin. My concern is not toxicity or fire hazards. I'm just wondering if there would be moisture concerns with my proposed installation method. I should have been more clear I suppose - sorry.
 
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Old 03-10-22, 03:24 PM
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Your asking for approval for something that is not acceptable, not going to happen!
 
 

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