I currently have a post going in the full restoration forum, and am just about to the point where I pull off the old OSB subfloor and put down a new one. This is a '99 Starcraft, and the existing subfloor is an OSB of some sort that was painted/stained black underneath. I have done a ton of searching and have not found a consensus among people, so I am looking for direct feedback from you guys. 1) Do I use Marine Plywood (fir, probably), or an exterior OSB? I am leaning towards a plywood of some sort, because it seems that it reacts to water a bit better than OSB, but I am looking for thoughts on this. we will be putting a linoleum/ vinyl flooring over it. 2) Do I seal it underneath in any way, or leave it bare? I will probably paint/seal/cover with something all of the edges and cutouts and holes through the wood, but I'm looking for experiences that you guys have had who did this already. Did your method work? What would you do if you had it to do over? I believe I have a way to keep the water out of the corners of the walls, so water coming from the top should not be a problem anymore. Anyways, looking for info on what I should do with the subfloor. Thanks!