The foundation of the cabin would be built on cement columns poured in place with rebar reinforcement rods installed to prevent cracking. At the base of these columns would be a "big foot" base designed to keep the column from moving in the ground.
A laminated beam built from four 2" x 10" PT planks would be bolted to the top of the cement piers forming a solid foundation perimeter for the warming hut.
A marine plywood floor will be installed on top of PT floor joists. Under the floor, rigid foam insulation will be installed and then a double floor will be installed to prevent moisture, bugs and critters from getting into the cabin.