Quote:
Originally Posted by hamsterpower
The spray foam I used is rated at R-7 per inch x 3 inches = 21, plus 5 more inches of cellulose at R-3 per inch = 15 + 21 = R-36. I added a second offset 2x4 stud wall for the extra thickness, so thermal bridging is minimal.
|
hamsterpower,
Without a doubt, you are doing this the right way... possibly more right than you realize...
Your 3" of foam on the outside walls not only gives excellent R-value, and a complete seal against infiltration, but it also sets up a thermal gradient, such that moist air will never reach the dew point inside your cellulose fill.
Just couldn't be better.
Had I started with the knowledge I have now, and the technologies that are available now, I would do exactly what you are doing.
As it is I will probably do a variant of your method on the next room I tackle. My little house is only 700 square feet, and I'm trying to minimize intrusion into my living space... so some balance is called for here.
The offset studs idea is great... I think I can do a version of that, next room.
Great advice, great work!
-AC_Hacker