I will be building a 22×18 log cabin tiny home on some very Rocky soil in North Georgia. My plan was to use a pier system w/Bigfoot style concrete forms and 8-in sonotube. I’m looking for thoughts and feedback on my planned integration of subfloor and first course of log. I plan on using a 2×12 double ledger, glued and through bolted to the inside of the first course of log, with 2×8-in floor joists. On top of the floor joists, my thought was to use 3/4 tongue and groove ply, a layer of 3 in blue foam, a layer of ice and water shield on top of the blue foam, another layer of 3/4 tongue and groove ply on top of that, and finally the finished 3/4 in White oak hardwood flooring. Underneath the entire floor assembly, I was thinking of using one quarter inch thick masonite sheet to close off the underside of the flooring system to the elements, critters and insects.
I believe that would provide a warm floor, without the use of fiberglass insulation in the floor joist cavities that can become moisture laden, and prevent thermal bridging because I am using 12-in OC spacing for the floor joists. From ground level to the underside of the subfloor is approximately 24 in. I was not going to skirt in the underside, but leave it open for ventilation.