As on all upper bathrooms with wooden floors due to movement; which could cause the tiles to crack; plywood should be laid first. In this instance a new product on the market called plastic ply was laid. This is slightly more expensive than wooden ply to lay, but as it is thinner and easier to cut it keeps the finished floor level lower; thus it should be on a level par with carpets in the next room and hopefully prevent you from having to remove the bathroom door to plane the bottom so it can still shut.
The floor was first prepared with tile primer, the plastic ply then stuck to the floor and the tiles laid on a rapid-set floor adhesive cut to suit sround the toilet and sink.
The tiles were then grouted and cleaned to give the finished look.
