After install a new shower/bath mixer, I am proceeding to restore waterproofing behind the mixer follow by the tiles.
Originally between the water pipes and the tiles there is a layer of gyprock (drywall, plasterboard) where the waterproofing to be applied on. Now that I bust into the wall, it is lack of solid surface and I wonder what is the best approach to go from here?
One of the easier option came up my mind is to knock out the remainder of the 2 broken tiles without removing the gyprock behind. Apply a soft net over where I can brush waterproof primer and coatings over. After that, apply tiles as normal hoping there are enough ground on its corners for the 2 tiles to sit dry.