I'm working on remodeling a 2nd floor bathroom, with the intent of putting tile down. After pulling the vinyl squares up, I had this:
(The vantiy will be going as well shortly, the tub is staying). The subfloor looks pretty beat up, some chunks are missing, etc. I would like to replace it, the question is how. The joists underneath are a truss setup:
The OSB has this marking underneath:
That is 18" high, 24" O.C. The bathroom is 5' wide, 8' deep and the joists run in the door to the tub direction. In addition the OSB that's down is not flat at all - there's a rise near the toilet, and the entire floor flexes when walked on. It obviously needs leveling and strengthening if my tile is to stand a chance (even with Ditra going on top, and Schulter themselves say a second layer of ply is needed anyway for 24" O.C.)
If I cut out the entire floor in the bathroom, I'd only have two joists length wise to tie to (of course in the middle) and nothing width wise nor along the edges. Is this worth persuing? Should I just put a new sheet on top of the OSB? I can't afford to be taking out walls, and I'm not really clear on how I would support replacement OSB the easiest. My good friend Google is letting me down as well, with those trusses down there how to install/secure crossbeams is not obvious (at least to me).