If it's done well it will last but not using 6mm ply.been thinking about this thread all day.... simply put... i have never seen a tile lift from a well installed, primed section of plywood with a decent adhesive and a well laid tile. as i said, the bastard is in the number of screws you need to go through to make the ply overboard totally inflexible... and in response to aussie tiler.... you are effectively creating a cross ply section with overboarding which makes it vastly stronger. like anything, if it is done well it will last.
Couldn't agree more, but sometimes some people just have to learn the hard way😉If it's done well it will last but not using 6mm ply.
Honestly you need to move with the times & get away from fixing to ply, it's just not stable a surface to tile to these days.
Hardie or thermal will give u a far superior bond & wont suffer from the same expansion or contraction that you get through ply.