This is a project I started in the spring and I still have a long way to go. Adding a 12′ × 16′ addition to our living room . Most of the wood came from a local burn pile . Some one had painted their deck with a special type of paint , well it peeled off so they put down new boards . I went to the pile one day and got 25 pieces of 2″ × 6″ × 16′ boards and half that many 10’ long. Later in the year I got 20 some 1″ × 2′ × 12′ boards , which we put on the bottom of the floor joist to hold up the 5’ wide x 1/8" polyurethane strips to protect the insulation. I have R41 in the floor . 2 layers of R11 and 1 layer of R19 fiberglass. I built the roof in sections in my garage and put them in place with a tow motor and a jib crane attachment . I covered the shell with 3/8" plywood , then house wrap and then vinyl siding . Got it weather proof just before winter. Working on the wiring now.