Your shower surround keeps water from coming into contact with the wall behind it. While it probably does a decent job, the drywall above the surround may suffer from water that sprays up or from moisture that accumulates on the drywall. One way to protect the wall above the surround is to install tile. The tile, when grouted and sealed, acts as a moisture barrier, protecting the wall and keeping water where it belongs…in the shower.
Measure each proposed tile area above your shower surround and draw a matching, to-scale outline on a large cardboard sheet. For example, if one wall's tiled area will measure 36 inches wide by 18 inches high, you would draw a rectangle that is 36 inches wide and 18 inches high on a piece of cardboard.
Layout your tile pattern on the cardboard template. This gives you a visual idea of what the tile will look like before you transfer the tiles to the wall. Use tile spacers if you want distinct grout lines.
Use a tile saw to cut edge tiles that are too large to fit and to cut tiles for making patterns.
Pop a chalk line on the wall to represent the top line of each tile row. Measure up from the corners of your shower surround to the height of your tile. For example, if you're installing 4-inch tile, you would measure up 4 inches on the wall and pop a level line.
Spread tile glue on the wall above the shower surround with a notched trowel. Read the recommended notch size on the glue container. Spread the glue on evenly, covering the area where the bottom row of tile will go.
Transfer your tiles, one by one, to the wall. Once the tile is on the wall, you have only a few seconds to fine-tune its placement before the glue sets. If you're using spacers, hold a spacer against the edge of the last tile with one hand while you place the new tile right next to the spacer.
Add the height of the tile, plus the width of your grout line when popping the next chalk line. For the 4-inch tiles, add 4 inches to the grout line, estimated here to be 1/8-inch thick. Pop the new chalk line 4-1/8 inches above the top of the first tile row. Check it for level.
Continue gluing and placing the tiles until you've completed that wall. Repeat the procedure with any adjacent walls that may extend above the shower surround.
Fill the joints between the tiles with your choice of grout or silicone caulk. If you're using grout, apply a sealer to the finished grout as directed on the grout package.