Outsulation – best way to install on roof and walls?
I’m building in Whistler BC, Canada (climate zone 6) and I am planning on adding 2″ of rigid insulation to the outside of all roof surfaces, and 1″ of rigid to all exterior walls (XPS rigid insulation).
The roof is an unvented cathedral ceiling with 10″ of spray foam insulation between the engineered rafters. The walls are 2×6 with spray foam insulation.
We plan on sheathing the roof with plywood, then installing 2″ of rigid insulation (taped seams), and then covering the rigid with another complete layer of plywood (then ice and water shield, with standing seam metal roofing). We plan on doing the same plywood/rigid/plywood rigid sandwich on the walls.
Is there any professional out there who can comment on the above plywood/rigid/plywood sandwich approach – and if this approach is a good solution vs leaving an air space and strapping the outsulation so there is an air channels between the finished siding or roofing and the outsulation?
Thanks in advance,
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