2 layers vs 1 of outsulation?
Greetings from Fort Worth, TX!
We are finalizing our house layout and I have been looking into various wall systems. I’ve about settled on 2×6 advanced framing dense packed – Zip Wall or OSB with Wrap – 2″ foil faced iso tapped.
This should give me roughly a R-25 wall.
My question is; not including labor, material cost is roughly 50% higher to do two layers of 1″ vs 1 layer of 2″. If I have a WRB and air barrier under the foam is it really necessary to have two layers?
I understand the benefits of offsetting seams, but is this really a belt and suspenders situation when I would be OK with just the belt?
Any help is appreciated!
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