Adding double stud wall during remodel?
I’m in Salem, Oregon and converting a workshop that is attached to my attached garage (one wall shares 15′ with the garage and ~5′ with the house) to a home office/movie theater and am wondering what the best approach would be to try to get this room to be comfortable year round without putting in a mini split.
The room is about 7’6″x20′ with 2×4 walls and a vaulted ceiling, however I’ll be adding a ceiling at about 7’6″. The walls outside to in are clapboard siding, hopefully some kind of wrap but I haven’t had a chance to try to pry back any siding to check, a type of particle board with some kind of asphalt facing on the interior side, and r-11 paper faced fiberglass. Another detail is the garage wall has ~12″ tall stem wall, the 20′ exterior wall only has a 12″ stell wall for a few feet before transitioning to the mudsill just being on the slab, there’s no exterior doors and two windows.
My plan right now is to put tyvek up on the inside face of all my walls as an air barrier and then build an interior 2×4 stud wall and use r-15 unfaced batts then drywall over that. For the ceiling I’m going to use the new attic space as storage so plan on 2×8 joists filled with fiberglass batts then 1-2″ of EPS with taped seams and then 1/2″ plywood on top. Additionally I plan on putting in new windows and the smallest ERV I can find. This seems like a fairly economical approach to trying to get a room that can be used year round without any kind of heat or cooling but I don’t know if there’s anything else I should be concerned about? Or if there is an alternative approach that might work better for my situation?
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