Zone 6-7: exterior wall assembly with a high R-value
I had asked a question yesterday regarding high R-values in the wall assembly. Thanks for the great answers. After researching more blogs & answers I think i’m still confused on the best way to go in my climate as the risk of vapour and frost ?
2×6 wall 2’o.c. roxul r23 in cav. / ext.-taped air tight 1/2″ plywood/ 2 layers 2″ polyiso taped/ furring 1×4/ext cladding.=r49 — R 43 cold climate? Still shy of R50-60
If I tape the plywood air tight, is there any need for poly air barrier inside?
Could I add a 2×4 service wall with R15 to bump R value- or add another 2″ polyiso on ext.?@$1.25sqft. or soes the cost of getting high R values for 90 days of the year not a good ROI?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part