The flooring tiles are wafer board on a ribbed plastic base. The idea is to allow air floor beneath the floor for insulation and to clear out moisture.
The threshold is red oak.
The strapping is ferring that is sold at Home Depot in 10-packs.
The walls are thin grade plywood. I originally wanted to go with decorative wood until I learned that they release toxic gas.
The insulation is simply layers of Reflectix.
The blue box is the dual battery system, currently disconnected while we wait for a missing part.