Floor Repair

Id still suggest adding the outriggers under there, the wall loads need to be carried back to the frame rails, and half inch of plywood and a few thin pieces of floor metal wont do that. It's not the weight of a couple of people, it's the loads (and 2 plus g's bump loads) from the entire wall and roof structures and everything attached to them.

I agree with you about the rpod throw away design. Cheap and light but not something anyone should expect to last very long. One reason I sold mine since I wasnt expecting to be able to use it for a few years. I'd rather just get another trailer when I need one again rather than try to maintain one in storage for several years in a humid environment.

The problem is that the floor structural strength resides primarily in the laminated plywood/foam sandwich, which acts much like a structural insulated panel (SIP). The floor metal framing is not where the strength is. So if water damage has compromised the floor panel the edges of the floor which cantilever out past the main rails (which are inboard) will sag under the load imposed on them by the walls.

Many folks have reported this problem abd some have even had the floor metal framing spot welds break.

So even if you get in there and replace foam and plywood you should add outriggers underneath to support the floor. There isn't any way to effectively recreate the laminated sandwich construction of the original continuous floor when patching in foam and plywood.

Probably it would be as effective and much easier just to jack up the walls and floor till things are level, install outriggers and underfloor bracing as required, pull up the vinyl, let the floor dry out, then lay down a new layer of plywood, new finish flooring, and be done with it.

You can use a moisture meter to ensure the old floor is dried out. Even in the southeast running the air conditioner and a space heater simultaneously (so the air in the trailer has as low humidity as possible) for a month or so ought to do it.

When FR gets the undercarriage the first thing they do is put down the floor, the lino then the walls. If they put the walls up first, the floor would be floating all around the perimeter.

If you have significant floor damage/sagging around the perimeter you have to find a way to lift the walls off the floor and replace the lauan plywood in the floor sandwich. I don't know any other alternative because the floor sandwich supports the walls. Granted that its not fun or easy.