After a year of delay, I am back to designing a foamie lift-up hybrid which will be mounted on a boat trailer. It will be larger than average (14' to 15' in length and 7' wide) so weight is a major issue. Using plywood as flooring adds significantly to weight. Has anyone used a composite / SIP floor (thin plywood on both sides with XPS in the middle, potentially using PMF also)? Other thoughts? If so, what thickness should be adequate?
Wooden joists 24" on center will run cross-ways on the trailer, and we will have a joist running down the center length-wise. The trailer itself is only 5' wide, but the wheels extend outward 12" on each side, so I planned to extend the width to where the wheels are, thus making the trailer 7' wide. Thus maximum dimensions of each individual floor panel dimensions would be 24" x 30", while the panels outside of the main Frame would be 12" x 24".
Any thoughts?