Happy to help!
My city limits outbuildings in my zoning (R-1) to 200 sq. ft., so I did a 10'x20' shed. I built mine on a poured concrete slab and installed a 3/4" marine plywood flooring on 2x2 furring with 1-1/2" foam board insulation beneath the plywood (it's Minnesota). Since my shed was for woodworking, I didn't need interior walls to endure moisture, so I used ordinary 1/2" plywood. I did insulate the walls with R-13 craft-faced fiberglass and covered the fiberglass batts with 4 mil poly right over the studs inside. Tallahassee winters are certainly warmer than here, but don't know if you plan to insulate the walls. I suppose it gets chilly there some days in winter? I assume you will finish your interior walls with something moisture-resistant, like green drywall or cement board?
I bought off-the shelf 12' trusses for the roof, placing them 16" o.c. And I insulated above the ceiling.
I installed a subpanel in the shed with a 60A breaker in the main box feeding it. I have a 5000 BTU window ac for summer and a
5000W 240V elec heater for winter. That little heater will keep it around 65 on all but the coldest days.
If you have any questions along the way, feel free to PM me, as I check HBT often.
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