I am helping my son refinish a 5' X 7' bathroom in a 35 year old house that he recently purchased. Upon removing the bathtub, we discovered that the 3/8" plywood subfloor was heavily water damaged and replaced it with 1/2" plywood. The remaining floor, 3/8" plywood, topped with 3/8" homosote, topped with mosaic tiles, must also be replaced. Can we install a 3/4" plywood floor, with no subfloor, and new mosaic ceramic tile directly on top of that? The floor beams are 2X8 and are in good condition. Will the floor be strong enough?
If we must use a subfloor/finish floor combo, what do you suggest? We would like the height of the new floor to remain about the same as the old one.