Is it possible to tile over tile in a 4'x4' shower. The tile is 4" squares on the walls and ceiling. The floor is 1" squares. If it is possible what type of thin set do I use and what size tile would be best. The tile is in good shape now.
Is it possible? Yes. Is it practical? No. The biggest problem is going over the "trim" pieces -- the outside edges -- the bull nose. A new bull nose won't quite cover the old. On the shower floor you must break out an area around the drain so you can bring the new tile down to that level.
I would not recommend that you attempt this project (a pro would never do it), but if you do, make sure the old tile is completely clean. Then use a latex modified thin set that is rated to adhere to tiled surfaces. Go to a tile supply store.
John