The expandable foam worked a treat for gluing everthing together, and I am really glad I took the time to cut the fingers on all the boards. I think its about required for the thin stuff (1inch)
The roof is definitely the holder together of things. Just like the big semi truck trailers (All the strength is in the roof stringers)
If I were to do this exact build again, I would have painted all the wood first (Taping off any joint areas first) oh well..didnt get too much paint on me
The vertical 1x3s inside the box are inset a quarter inch into the foam (Routered the foam) and glued with Gripper or Titebond with some spraycan foam squirted into the edges for good measure. THe roof frame is then glued to these