The New Canaan House is closed in, sealed up, and passed its rough in inspection. Now it is ready for insulation. This house is a bit different than the usual ‘spray foamed’ energy efficient house in that it is wrapped entirely with rigid foam boards in one form or another and then the wall cavities will be filled with dense pack cellulose.
On the roof we have 4” thick sips panels that use polyisosanurate insulation board adhered to OSB boards. On the walls we are using Zip R sheathing which is basically the same thing but with only 1 3/8” of polyiso insulation board. We area also strapping the existing 2x4 walls to make them the same width as the new 2x6 walls to optimize dense packed cellulose R values.
The bottom line: Our total R value for the roof is about R50 and for the walls R26.
The crawl space will be foam insulation boards as well and we will achieve an R 30 there.
Plus all of the walls will be very well air sealed.
Pretty good for a retrofit!