I’m about to build a sauna on a 4″ thick concrete pad (poured 10 days ago) in Philadelphia. I’m going to start framing soon and I have a few initial questions…

-How should I seal the bottom plates?

-I’ve framed many indoor walls by building simple 2×4 boxes, but have never framed an exterior wall or freestanding structure. Is there a different framing technique I should use? Something to elevate the structure and subfloor above the concrete pad?

-How do you recommend fastening the stud walls to the foundation? I’ve got a very good hammer drill, though if I could get away with powder-actuated fasteners I might prefer that for speed…

FYI: The pad is 11′ x 13′, I’m planning to build the sauna 10′ x 12′, so there’ll be an apron of 1′ around the perimeter.