Is it ok to use 3/4 tongue and groove osb subfloor in a bathroom if I am going to be putting 1/2 cement board on top? Just wondering since the 3/4 plywood is so much more.
Thanks for any input.
OK if you are not tiling. If you are going to put tile down on the floor, then there are a lot of factors involved and the plywood may or may not be worth the extra cost.
Size of the floor joists.
Span of the floor joists.
Spacing (OC) or the floor joists.
Floor rated OSB or plywood.
Size and type of the tiles.
2x10x12 16" on center. The 3/4 osb board is tongue and groove floor rated. I am going to put 1/2 inch cement board and tile on top of that.
What is the joist size, span, species and condition? We need to know that before we can be sure the floor will support tile. Especially natural stone. You don't need 12: ceement board, 1/4" will do just fine but it must be set in a wet bed of thinset, then secured with the proper fasteners.
You'll fare well by heading on over to the John Bridge Tile Forum and checking out their library and deflecto-lator before posting a thread there.
John Bridge will have the definitive answer but if the "OSB" you're speaking of is "Advantek" I think you'll be OK. I'm a tough skeptic to convince when a new product claims to be better but Advantek is now my choice of subflooring period. No more plywood, this stuff rocks. Better moisture resistance, less flex between supports, and a harder surface for less denting. This stuff is not OSB but it looks similar. IMHO regular OSB does not belong in floor systems.