Huber Zip system R-6.6 sheathing and minimum foam R-values
In zone 5 (central OH), the minimum R-value of rigid foam for 2×4 construction is R-5 and R-7.5 for 2×6 construction. What would be the required amount for a 2×4 staggered stud wall on 2×6 plates? Would the Huber Zip R-6 (R-6.6) sheathing be adequate since it would only be in contact with the 2×4 studs staggered to the exterior?
Is the product comprised of multiple thinner laminations of OSB & rigid foam or single thicker layers of OSB with rigid foam at the interior surface? Reason I ask is that I heard that it was bad to create a sandwich of foam surrounding traditional OSB sheathing (ie. rigid to the exterior and closed cell spray foam at the interior). If multiple thinner laminations, would it be OK to apply either closed cell spray foam to the interior (ex. 2″ layer, followed by 3 1/2″ of either blown cellulose or blown fiberglass such as JM Spider’s product) or just apply either the blown cellulose or blown fiberglass by itself within the entire 2×6 cavity? Appreciate your thoughts …. thanks.
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