# Why not what I have for insulation?



## Build it jill (Jun 14, 2019)

i have an abundance of 1” thick closed cell foam that I would like to use for roof insulation. Previously used in the shipping industry, it meets fire mandates of the airlines etc.  . Can I insulate with anything as long as I can prove it has a high r rating and is treated for fire retarding?


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## cda (Jun 14, 2019)

Where do you want to put it??

On the roof ?

On the under side of the roof deck ?

On the top of your ceiling in the attic?

Do you know the R value??


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## mark handler (Jun 14, 2019)

Build it jill said:


> i have an abundance of 1” thick closed cell foam that I would like to use for roof insulation. Previously used in the shipping industry, it meets fire mandates of the airlines etc.  . Can I insulate with anything as long as I can prove it has a high r rating and is treated for fire retarding?


If this is in CA, Must meet CA energy code Requirements, Not FAA requirements.


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## ICE (Jun 14, 2019)

What is the R value?


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## mark handler (Jun 14, 2019)

ICE said:


> What is the R value?


Typically Closed Cell Spray Foam has an R-value of 6.0 - 6.5 per inch
But the product Jill is speaking of could vary

Problems do occur with spray foam including trapping moisture in the framing. This occurs when there is a moisture barrier placed on the outside and closed cell on the inside. trapping moisture in the wall.....


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## Enrgxprt (Dec 13, 2019)

Most of the times, the best place for foam is on the outside, but not knowing your climate location, if there already is a vapor barrier (plastic sheeting) under the sheetrock, and a few other things, could be a recipe for disaster.. 

HDF is certainly a vapor barrier, and you wouldn't want 2 of them (one both sides of the wall). That wall would have zero vapor profile (a bad thing). Any moisture that might sneak in would be trapped.. mold, mildew, rot and general yukkie stuff..

Describe how your walls are built, same with ceilings.. what part of the country is it? Do you have a basement? Viny siding, shake, stucco ??


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## mtlogcabin (Dec 14, 2019)

S California according to profile


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