Hi All, Just after some advice on the best way to approach the wall preparation of a job i have availability to start next week. The customer wants 400 x 300 ceramic tiles installed from floor to ceiling. Wall details; Outside window wall is constructed of concrete block and internal walls are 3 inch thermalite block. Previously the walls were tiled half height and full height in shower area and on removal it has removed areas of the bonding and plaster (nothing new). On inspection i highlighted to the customer that areas of the bonding had blown and that the best approach would be to remove damaged/blown areas and have them repaired by a professional plasterer prior to me tiling, as they're in urgent need for the bathroom they asked if over boarding would be a possibility, to which i replied yes having over boarded concrete block and timber walls with cement boards/waterproof boards etc etc, but inspecting the shower area walls where all the bonding and plaster came away with the tile has me questioning the longevity of dabbing and mechanically fixing boards through into the thermalite block, as most of the blocks are cracked and damaged. Any help is greatly appreciated. Please see attached pictures of wall condition.