Unfortunately, I am not talking about OSB (aspenite) but about a fairly coarse-grained particle board. Right now there is at least one layer (there may be two) of this stuff, probably 3/4 inch for the subfloor/floor on top of which there was carpeting. There should be low humidity since the floor joists are exposed in open/ unrenovated part of the house. If I am going to rip up the particle board, can I lay down a pine plank sub floor? I am anticipating one of my next projects which is to convert the area underneath this room into living space. If I have a plank subfloor I could leave the old beams exposed and it would look a lot better than exposed particle board or plywood. Would there be problems with warping or swelling if I went with the plank subfloor? Thanks.