To your point... There is no hardware going through the walls or outer skin. The Filon is not penetrated in any way other than the cutouts for the necessary doors, windows, etc. The walls have 2x2" cleats mounted at the bottom that make a "ledge" for the wall to sit on the flooring. 4" bolts go through the cleats into the floor and through the frame. In my original trial run, there was a substantial space between skirt and the frame, (intentionally built in) so yes, there is adequate allowance for the layer of fiberglass and epoxy. So... whether there is Filon on the outer wall or not, it makes no difference regarding how the walls mount to the frame. All the mounting bolts go through the internal cleats and are hidden by the bed, kitchen cabinets, dinette seating, bathroom cabinets and the closet.
One of my friends was looking at the design and asked if the bolts through the cleats are the only things holding the walls onto the trailer. Technically, the answer is yes. But realistically the answer is not entirely... because the walls are bolted and bonded to the internal walls, the dinette seating, the cabinets, the bed, etc.
The strength is in the sum of the parts...
One more thing, check out the pictures of the wall standing next to the 7' garage door to get a feel for the size of the walls. They won't go through the doors without being laid down a bit.
So many threads to follow, so much going on.
