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Insulating in the attic with spray foam

2K views 3 replies 3 participants last post by  Nailbags 
#1 ·
I recently gutted two closets down to the studs in my old house. I even took out all of the old plaster and lathe in the ceiling. I plan to sheetrock the new closets next week.

I've got no insulation right now above the closets. I was thinking about doing spray foam above them then sweeping some of of my blown in fiberglass over the top of the spray foam (I have a lot of blown in fiberglass up there, about R-60). Would it be ok if I just used some canned spray foam? The areas aren't that big, but I'd like to get the best air sealing that I can for maximum energy efficiency. Would this type of foam be a bad idea to be in direct contact with the studs? I know some people believe that open cell spray foam can hold a lot of moisture which might rot the wood.

Could I use a few cans of spray foam? Or should I look at a small diy spray foam kit? Eventually when I remodel my kitchen and my bathroom I will also gut the rooms down to the studs and I'd like to insulate above the rooms the same way. Thoughts? Advice?
 
#4 ·
Here is the problem with foam it does have its place like every type of insulation. there are places in the home that are not to be sealed up! one of them is the sheathing of the roof! you need that to breath. you need air flow over that and to have the heat cold exchange to have insulation work. This may sound crazy. but this is how a attic works your home is a certian temp in the summer. your attic is hot as heck. it move cool air from out side under the sheathing to keep the shingles from curling up! in winter time it colder then a brass seat in a out house in december in there. your home is nice and warm warmer air moves up through the vents and helps keep condensation off the sheathing saving you dry rot and mold and damp issues.
Spraying foam in to places like that disrupting the air that your roof needs to breath right. is bad. now for the fun part. say you have it in place you get a torn shingle from a wind storm and leak happens and you don't know about it. water builds up goes down the foam to the top plate and down the back side of the 2x6 extiror wall and you don't even know about it till you find mold problems and roof rotted out and walls full of mold. that is the nasty of foam. as for using GS won't work you need to sray it on with a high psi. hope that helps
 
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