Is this a risky wall assembly?
I am in the process of finalizing plans for a 2 story 2385 square foot home in Zone 6 WI 44.3353° N, 88.6389° W. I have been trying to get in the pretty goodish house category as far as insulation levels and while not where I’d like them to be am currently sitting with the following setup due to budget.
R10 EPS below slab insulation
R10 EPS exterior Foundation walls (will finish off basement later and can add interior insluation)
2×6 R20 damp spray cellulose with R7.5 Atlas Thermalstar LCI-SS EPS insulated sheathing
R55 blown cellulose attic insulation
Single Hung Alliance U .29 Windows
It just seemed anytime I tried to bump any of these components up any higher the price tags went up exponentially.
The only real concern I have right now is the wall assembly as I know with the exterior foam is below the minimum threshold for my zone and there is the potential for some wintertime condensation in the wall.
My question is – is this wall assembly inherently risky. I know with exterior foam its go thick or go home, but being only R4 away from the threshold where there would be absolutely no winter time moisture accumulation and by planning on adding Certainteed Membrain smart vapor retarder on the interior side of the wall and having cellulose in the wall cavities with some moisture absorbing capabilities am I mitigating this risk?
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