This detail illustrates newly installed ceramic, gauged porcelain, stone, or glass tile on existing gypsum board backing on existing gypsum board backing on existing steel or wood studs. This is a retrofit application for use on interior walls in dry areas only. The tile is adhered to the existing gypsum backing with a cementitious bond coat of latex-modified thinset mortar. The mortar manufacturer may require a primer or bonding agent. For an existing steel stud framed wall to be a candidate for tile retrofit, the studs must be 20 gauge or heavier, a minimum of 3 5/8 inches thick, and spaced at 16 in. on center maximum. Optional profile strips are shown at the outside corner, and vertical expansion joints in the field of the wall are spaced at specified intervals. This detail is based on the Tile Council of North America (TCNA) method W243.