Originally Posted by family wagon
There will be a layer of sheet metal down there; the only question is whether there is a layer of plywood between the rubber and the steel. The steel layer must stay because it's the last thing standing between interior and exterior. Wood wouldn't resist weather under the bus as well as the factory steel does. .
Actually, my 1988 Gillig Phantom has no metal under the floor, just plywood. I took up a section, and can see down to the road. And it's still in good shape, other than a section by the front door/wheel well. Of course, it was used in California it's entire life, but still - 28yrs and still holding strong is not bad. It does have the full-width storage bays under it, which protect a big part of the floor, but those storage bays are ALSO just plywood, with no sheet metal under them. Again, totally solid. I've crawled in there and checked. I suppose those could have been replaced at some time, since that would be relatively easy to do, but I see no evidence that they have been.
Honestly, I'm a little shocked, because I would have assumed the plywood wouldn't hold up, but it seems to be good thick, marine grade plywood, so has done fine.
I'm going to be taking up sections of it, since I'm planning on a step-down shower, as well as a few in-floor storage areas, but overall, I'm going to be able to leave most of it in.