Hi all, I'm going to plasterboard my bathroom for tiles. The bathroom was half tiled before so walls are at different levels. Where the tiles have been removed I have a crumbly grey cement like layer and then brick behind. Tops of walls are ok ish as they were plastered and painted. Another issue is that I have knocked through the toilet to bathroom and the walls are at a different level also. My question is what is best way to go about the job of fitting plasterboard. Should I remove all plaster and crumbly layer right back to brick on all walls and then fit MR plasterboard straight to brick. I would prefer to screw it. I really want the easiest way but dont want to end up with issues later on. Any help appreciated.