Installing mitered tile is similar to installing regular tile, but a mitered tile is cut at an angle that will finish upright work at the corners of an external corner. An external corner can be found indoors or outdoors. In this sense, “external” simply means that the corner extends outward into the room. Outer corners measure 90°. If you wish to install tile in these corners, you must miter each side at 45°. This article will show you how to do that.
Step 1 - Take and Transfer Measurements
Measure the wall from the outside corner on either side. Then transfer the measurements to a piece of tile by placing a pencil mark on the top where the pieces will align with the wall.
Step 2 - Cut the Tile
Put the tile on the miter saw. Next turn the saw 45° away from the tile so that the mark toward the back of the trim aligns with the blade. It should also point away from the measured span. Start the saw and bring the blade down through the tile. The front of the tile should be longer than the back when you are finished.
Step 3 - Repeat for Other Pieces
Repeat Step 2 for tiles on the opposite side.
Step 4 - Set the Tile
Hold the pieces of tile at the corner of the other tile piece where they will be joined to make sure they fit together well. Spread some thinset mortar and place the tile. Finally apply grout on the seams to finish your work.