Bathroom wall prep - Tile Advice

[Tom TGH Tiling]

Hi guys, I'm currently re-tiling my own bathroom. My plan after ripping off the old tiles was to prime with sbr, level with rapid set adhesive, then start tiling. Looking at the wall I'm thinking I should take off all the plaster, then mechanically fix marmox boards onto a bed of adhesive then go from there. There's not enough space to add a timber frame.... any thoughts and advice appreciated, thanks, Tom 👍👍

 

[rabw]

Is it sand cement behind the plaster? Can you just take it back to sand/cement?

 

[Dave]

If you have sufficent room , just dry line it.