I have gutted my bathroom, the subfloor is 5/8" construction plywood on 16" centers. Subfloor is in good shape, but I can fell a bit of flex in the floor between the joists even after screwing it down.
The plan is to add Schluter uncoupling membrane, then 8"x8" tile.
Technically, the Schluter membrane says 5/8" plywood on 16" centers, so I do meet the spec. It also looks like OSB is approved, so my plywood has to be better than than the minimum spec (5/8" OSB 16" OC).
Should I just go ahead and add the Schluter (this is my inclination)? Maybe add some 5 mm cedar plywood underlay (glued and screwed)? Pull the floor and glue/screw 3/4" plywood?
