An internal trim that can be used with ceramic tile, sheet or board, wood or even carpet. It provides cover for the rough cut edge for horizontal or vertical angles. Used in conjunction with a silicone it can effect a seal as long as there is no movement expected.A larger profile (code EKI) can be used as a floor baseboard keeping the dirt out of the corner.
This internal trim can bridge a gap caused by movement of both the underlying surface and the vertical tile or board. You can also make a seal by applying a small bead of silicone underneath and behind the front face of the profile, before fixing your tiles.