I'm reasonable ok at most diy but i'm thinking of tiling the bathroom with marble tiles. The wall are plastered and that seems sound. When i removed old tiles in the kitchen with a chiesel the plaster stayed on the wall. I intend to tank the shower area with MIRA waterproofer. I've only tiled a little in the past but all are still on the wall and look good - to me at least. Can you offer any advice and suggestions that can help?