Since the last time I posted, I’ve doubled the width of the 1x boards and added three cross beams. I’m taking 1×8 boards and ripping them on my table saw to a perfect 1″ width which here is vertical to match the thickness of the foam. I can get 6 1″ boards out of a single actually 7.25″ 1×8 with a .5″ strip left over. Then I’m gluing two of them together to make a 1″x1.5″ board. More work and more glue but not as much waste as ripping 2x2s. Then three cross beams directly over the cross beams on the trailer. Double thickness as I’ll be running bolts through them in places to secure the floor.
Then the rigid foam and the top layer of 1/4″ plywood that will be the surface I walk on. The bottom plywood is 11/32″ BC exterior plywood, the top is 1/4″ “RevolutionPly” which is called interior but supposedly made with with exterior glue. I got three sheets of that for the cost of 2 exterior sheets of the same price. Hopefully that was not a mistake, so far so good.
Next step will be to drill some holes and secure the floor to the trailer, then adhere the foam to that, then glue and staple the top to the foam and 1x lumber.