Celebrating a Lesser-Known Role of Hamilton: Father of the Coast Guard 2 Â· 1 comment President Trump to give keynote speech at US Coast Guard Academy in May 2017.
First, You don't Tile over Drywall in any case in Bathroom area exposed to Moisture etc.( you may have to remove existing drywall& install cement board, around that area for better results of tiling. Second. The drywall should not be, less then Blue Board for all areas except Shower or bathtub tiling.
If it's going to be around a bathtub, you need to install cement board, then put fiberglass mesh over the seams and seal with a smooth layer of thinset. If this tiling/mosiac job is in the kitchen or not going to be exposed to water like the tub, then you can tile directly on the wall.