I am a DIY but have many years of experience building structures and additions in VA. Moved back to NY and want to finish an existing room that is roughed in (was a garage at one pt). The floor is a concrete slab, the walls are 2x4 16" OC. I have a few questions; (1) would it be smart to build a sub floor on top of the slab before finishing it and if so would 2x4 or 2x6 be enough? Can I insulate it? Should I put a poly weather barrier between the slab and sub floor? (2) should I insulate w/ R13 in the 2x4 walls or add 2x6's to get R20? Thanks so much for any and all advice.
is there a slope to the concrete slab?
what is the distance from existing dwelling finish floor to the slab?
what is the existing ceiling height in the garage?
is this in NY state or NYC? (different building codes)
is there a man-door? (hinged door)
one or two overhead garage doors?
is the wood wall framed above the concrete slab (does foundation extend above slab)?
depending on answers and how you'd like to approach there are several ways to address this.