Fiberglass-clad sheetrock as vapor retarder?
I live in IRC zone 5A Pennsylvania. I’m insulating the walls of my kitchen; it was gutted to redo the wiring and the plumbing. There are two exterior walls a north and south side an uninsulated garage on the east side and the main house on the west side.
The exterior walls are clad with vinyl siding over house wrap. The corners of the kitchen are sheathed with ¾ inch plywood –the rest is clad with ¾ polyisocyanurate (PIR). The framing is 2×6, 16 inches OC.
I plan to install 6 in rock wool batts in the stud bays after caulking junctions where the sheathing and studs meet and filling the wire and pipe penetrations with foam. Finally I was planning to cover the wall with fiberglass clad sheetrock. The sheetrock would be later be painted with latex paint. My question, do I need a vapor barrier or vapor retarder other than the painted sheetrock?
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