ditra

I'm retiling my hallway. The previous tiles were on 12mm ply, laid over the Victorian floorboards. After lifting that ply, I've found a gap in the floorboards from where a doorway was moved (see link). In the gap there's the old base of the wall. The centre of it is almost but not quite level...

I have to start tiling my upstairs bathroom and got opposite opinion between sticking hardiebaker or using ditra matting before applying the floor tile. What your opinion on this and what would be the best reliable way? Thanks

Lots of forums on this stuff but not the exact question. I have 3 wetrooms, 2 on ply and 1 on concrete. The plan was to sink a section for the shower area 1500 x 900 and envelope tiles into it but need to waterproof the rest of the room. The tiler has quoted to use Ditra mat with a section of...