Is my wall design OK?
I am in zone 3A, Fort Smith, AR.
I understand that for this zone, I do not need any foam board insulation on the exterior of my wall sheathing to prevent condensation on the interior of the sheathing.
But I am fairly close to zone 4. Should I add some foam just to be sure ?
I am on a limited budget and would rather not if it’s definitely not necessary.
The wall will be (from the outside inward):
Vinyl siding, Advantech Zip panels for the sheathing (joints taped with Zip tape), 6″ Roxul batt, drywall, latex paint.
Also, Advantech says I don’t need felt over the Zip panels (neither for wall panels nor roofing panels), but should I add a layer of felt between the vinyl siding and the zip wall sheathing anyway, or will the looseness of the vinyl on the sheathing be enough for a drain plane.
Finally, I’m concerned that the denser resin in the Zip panels, along with the joints being taped, will make the sheathing nearly as much a vapor barrier as poly sheeting, thereby limiting any wall drying to the interior only. Will this be OK ?
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