Double-bullnose tiles work well for outside corners.
In construction, a bullnose shape refers to a rounded edge. For tiling, workers mostly use regular, square-edge tile for the interior portions of an installation. For the outside borders, they use bullnose tile, which has a rounded edge on a single side. The rounded edge provides a finished look and transitions well to the surrounding walls.
Function
Double-bullnose tile has two adjacent rounded edges, making it suitable for the outside corners of rectangular tile installations. For example, imagine a wall-tile installation that is roughly rectangular. The inner portion consists of regular, square-edge tiles. The outside borders across the top and up the vertical sides consist of single rows of bullnose tile, creating even, rounded edges. At the top right and left corners are double-bullnose tile. At each corner, one rounded edge completes the vertical border, while the adjacent rounded edge completes the horizontal border.
Transition Problem
Tile workers also use double-bullnose tile for transitions between adjoining walls. For example, imagine a single border of bullnose tiles across the base of two walls that meet at a 90-degree outside angle. Recall that the horizontal side of the tile border is rounded because the worker used bullnose tiles, which have one rounded edge. That means the leading vertical edge of the tile installation is square. After the tile worker installs the last bullnose tile on one wall, she must find a way to create a tile transition that matches the 90-degree outside angle where the walls meet.
Solution
To create the transition, the tile worker installs a double-bullnose tile. Its top rounded edge continues the horizontal rounded border of the preceding tiles. Its adjacent rounded edge covers the jutting square edge of the last tile in the other wall's border. The effect is a finished, rounded edge that meshes well with the 90-degree angle where the walls meet.
Considerations
Create a detailed sketch of your planned tile installation so you can order the proper number of regular, bullnose and double-bullnose tiles. Most tile installations require relatively few double-bullnose tiles (in comparison to regular and bullnose tiles), so your hardware store might have a limited supply. If your installation calls for many double-bullnose tiles, you'll likely have to special-order them.
Tags: double, bullnose, tile, used, rounded edge, adjacent rounded, bullnose tiles, double-bullnose tiles, 90-degree outside, 90-degree outside angle, adjacent rounded edge
