Insulating shared wall in the attic of an attached garage
Hi Martin, All,
I am planning to put some rigid foam on a shared wall in the attic of our garage (conditioned space on one side, unconditioned attic on the other). As shown in the attached picture, Tyvek is covering the sheathing of the shared wall. Without windows or bulk water concerns it seems pretty straightforward, but there’s a 2×6 roof rafter directly against the Tyvek / sheathing
– If I put 2.5 inches of polyiso on the wall (i.e. 1.5in and 1in layers with staggered seams), I will effectively cover the first rafter with foam on two sides. Any concerns? I assume that this rafter can still dry in multiple directions if it happened to take on some moisture.
– The wall will be able to dry inward and I will pay attention to air-sealing. Anything else to be concerned about?
Thanks and regards,
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