So we're saying this floor hasn't failed? We are talking about removing tiles etc im guessing not.
Im sort of inclined to agree with Widler. Sounding like im the only one. But IF the floor is deflection free after removing tiles and in reasonable order then id clean up and prime the 6mm ply putting in more 25mm screws to ensure its well fixed to the chipboard. Then i would glue and screw hardie backer over the top. Then tile.
6mm ply is pish for an overlay. But fixing hbb over ply is more preferable than chipboard anyway.
bloody traitor......:lol: