Roof Insulation on Remodel
FloatingAdrift
| Posted in Energy, Heating & Insulation on
I am renovating a home we bought recently which has a cathedral ceiling. The roof structure is comp. shingles over 1.5″ rigid insulation over 1.5″ T&G. This assembly sits on the 4×10 rafters with the T&G exposed to the interior.
We want to raise the R Value to 38 as economically as possible.
My question is how to build a working insulation system over the existing rigid insulation to reach that R38? It looks like it’s RMax which should be 9.6 R Value. What would be the least expensive options for either a vented or non-vented assembly to get that to R38?
Replies
Cheep in the long run is often costly up front.
I was shocked at the very low price quotes I got for closed cell spray foam last summer so I had three attics done that way. Apparently the price has really come down a lot or else contractors are hungry in Chicago.
Insulation is more than just R value, this stuf is a total air seal too. The results are very impressive.
In my humble DIY opinion, this is a no brainer choice. Just don't get seduced by the cheaper open cell foam, which could yield roof rot issues in this application.
Good luck.