I have a 24 ft BT Cruiser, 2005. It is the version (5230 I think) with 2 jackknife sofas (rather than dinette).
I just discovered the slide out has been leaking badly probably the whole time I've had it (2 years). The slide underbelly waterproofing plastic sheet does not allow the water to escape - so the plywood used in the subfloor has been damaged.
My slide out has a single rail, electric rack and pinyon gear mechanism, of the "above floor sofa slide out" type.
My slide out floor is made of a 1 in thick metal frame sandwiched between two slabs of 1/4 in plywood. The long edges of the floor are 1 in thick solid metal (not sure how wide yet), joined by 5 ~4 in wide x 1 in thick x 30 in long solid metal slats. Between the metal slats is blocks of 1 in styrofoam insulation. On the bottom is plastic underbelly sheet material. The mechanism rail rests on the central metal slat.
The metal frame is very sturdy and there's no evidence of rust.
The 1/4 in plywood on the top is only damaged at the edges, but the 1/4 in plywood on the bottom is totally destroyed by rot.
So far I have removed the underbelly plastic sheet and the rotten plywood on the bottom.
Things I need help with:
1) I wonder if this metal floor is the way all slide out floors are made? I am a bit confused because in my research I got the impression that people are replacing their rotted subfloors with marine plywood, and no one mentions metal framing in the floor.
To me, the 1/4 inch plywood doesn't seem to be doing anything except holding in the insulation, and providing a solid surface to apply flooring to.
2) I wonder if anyone else has realized that the moisture barrier plastic underbelly is kind of a bad idea, and if they have tried other materials? I saw that one guy used marine plywood and marine spar varnish rather than moisture barrier. Since the bottom of the slideout isn't actually ever subjected to road dirt etc. like the actually underbelly is (given that the slide out is always retracted when you travel) I wonder if it wouldn't be better just to put some actual insulation across the bottom rather than plywood and moisture seal.
3) Mostly, I wonder if anyone has had a similar experience to mine and what you did about it.
I haven't decided if I will take the slide room out - just to see if anything bad is happening under there. One of the gliders pulled out of the floor so I know there must be some damage to the coach floor too.
Thanks to anyone who has read this and has any ideas for me. Here is a (very bouncy and probably not very helpful)