I am residing and improving my insulation currently. I discovered rot in my sheathing an am replacing it on my walk out basement with treated plywood.
My upstairs has osb still. I live in northern Wisconsin and it gets to -30 in the winter. My walls are currently siding, osb with no house wrap, 2×6 with fiberglass batt, plastic sheet, and drywall from the outside in.
My plan is siding, rain screen, liquid housewrap and joint sealer, sheathing, 2×6 with R21 mineral wool, smart vapor barrier, 2×4 with R15 mineral wool, drywall.
My question is will leaving the good osb be a concern for condensation with the added insulation or should I go with plywood. I’m ok replacing it, but obviously it’ll be way cheaper and less effort to leave it. I will not use exterior insulation as my eaves do not provide enough overhang for comfort.
Thanks for the help!
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