We are building a low sloped roof over our new kitchen addition (roof
pitch will be 2/12 pitch or lower. We will be using a solid rubber roof
, but this post is about the insulation and I digress....
We were at the home show this weekend and I talked to a spray insulation
company. We have considered using closed cell spray insulation since
this attic space will be limited in room and it seems to offer some
The spray insulation company indicates 1" to 1.5" of closed cell foam is
enough. At 6 "R Factor" per inch .... it doesn't make sense to me that
1" to 1.5" inches of spray foam is enough. But the company indicates
that air infiltration is the key with spray foam .... and that "R
factor" isn't as relevant...???
Is this accurate .... This ceiling is in our home in NE Oklahoma.
Normally, ceilings have R-30 or better. But at 6 R per inch (for spray
foam closed cell) ... do I need 5" to get up to R-30??