How To End Tile On Outside Corner . Use the same method to install your trim tiles as you did your other tiles. I absolutely love to use a slab material as a transition when i can. tile How to finish tiling an outside edge for a shower? Home from diy.stackexchange.com On the flat wall i ended the chair rail with an outside corner piece and cut a field tile around that outside piece. Use the same method to install your trim tiles as you did your other tiles. The tile edges have the red ceramic color and after reading your blog, i am now concerned about the grout option.