Hi,
We are getting ready to build a house in St. Louis, MO.
Please let me know what you think of the following wall assembly:
Inside – Out:
1/2″ Drywall
2 x 6 Stud cavity with Rockwool Batts
Zip Sheathing
2″ Rockwool ComfortBoard 80
Delta-Dry Rainscreen
Brick
With 2″ of exterior rockwool insulation, what size batts should we use inside the wall cavities? Zone 4a calls for R-20 walls. What is the optimal R value we should try to hit for our mixed climate? Thank you.
Replies
Your wall assembly looks good from an energy standpoint, but I can't comment on the brick since we just don't do much of that on residential here these days. (It's all LP smartside/Hardi or cedar here) You'd be much more likely to get some good insights on the building science aspect of this assembly over at GBA. http://www.greenbuildingadvisor.com
"what size batts should we use inside the wall cavities?" ...what size wall did you say you're building? 2x6? So, 2x6 batts are 5.5" thick and either 22.5 or 14.5" wide for your stud bay width. Or am I missing something in the question?