Is exterior sheathing over rigid foam board okay?
Articles regarding exterior rigid foam sheathing deal with it’s installation over the wall sheathing. What about the sheathing over the foam? I’m considering Huber’s R-Sheathing as a one step process to achieve both for a new home at the far north edge of zone 5. Their 1½” panel has 1″ of foam under their standard green Zip Panel with a total R-value of 6.6. While this addresses thermal transmission, won’t it also keep the sheathing colder? And doesn’t that cause issues of it’s own?
The R-Sheathing will go over a 2 x 4 wall with the intent of using blown-in cellulose in the wall cavities. Does this cause any issues? Thanks in advance for your feedback.
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