I may have stepped in it this time. At the last show I sold my camper yup packed my stuff and walked home so to say. It went west and I went east. Well I found a new camper through a friend, 20 years newer than the old one and with a slide twice as big. Now the hitch in my giddy up the floor is junk. Not knowing anything about how they made it I figure shoot I can fix anything and home it goes. I have ripped out most of the rot and still need to rip out the section that was still good. When I got it I was thinking fine I'll rip this out put in some new floor joists and ply no big deal. I start ripping it apart and find that the floor system is a SIP panel an aluminum frame goes around the outside it has 2 frame members that go from side to side. 1/4"ply on the top of an 1 1/2" foam and 1/4" ply on the bottom. So far the only plan I have come up with is to put new ply on the top and spray foam it from the bottom. I wouldn't be able to put ply on the bottom but if I use close cell and shoot it with undercoating it would be sealed up good.So lets hear some thoughts on rebuilding this floor.