Where to Put the Vapor Retarder on a Double-Stud Exterior Wall
I have a situation that I’m looking for some guidance on. There is a home in zone 6 (WI) that has a portion of the basement with a 1/2 wall consisting of poured concrete, with another 1/2 wall on top of that consisting of wooden frame construction. I don’t think this is unusual, but what was built in front of the top part of the wall is a bit unusual. It’s essentially a double wall.
So, what we have for the upper part of the wall (approximately 46″ vertically) which runs around two sides of the house (the rest of the house has full basement):
Vinyl siding cladding – Tyvek wrap – 7/16 OSB – 2×6 wall with dense-pack cellulose (R21) – Certainteed Membrain VR – 1″ gap – 2×4 stud wall with fiberglass insulation – 5/8 drywall – 5/8 drywall. The final intent is to use plaster on the inner layer of drywall (plaster base).
When I say “gap” it isn’t a true gap – it’s filled with fiberglass insulation – I just mean that the stud walls are separated from each other.
Should this be an emergency with the VR in its current position removed or cut up / added to interior wall? I know the typical way to install VR in this climate is on the inner wall between insulation and the drywall, but part of me wonders if this is air sealed from the interior very well (all drywall seams caulked and outlets sealed – used putty pads on backside of all outlets), and it’s only a limited part of the house, maybe it will be ok? Not an expert on the subject especially in this scenario – any thoughts either way?
This is a newer house, about 5 yrs old.
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