This detail illustrates the process of installing new ceramic, porcelain, stone, or glass tiles on existing gypsum board backing with steel or wood studs using a mortar bed method. It’s important to note that this method is specifically for retrofitting interior walls in dry areas. The tile is adhered to the existing gypsum board, which may need to be primed, over a mortar bed with embedded metal lath. The fasteners for the lath should extend into the studs. A cementitious bond coat of latex-modified thinset mortar is then applied over the cured mortar bed. For an existing steel-stud framed wall to accommodate this type of tile installation, the studs must be 20 gauge or heavier, a minimum of 3 5/8 inches thick, and spaced at a maximum of 16 inches on center. Additionally, optional profile strips should be used at the outside corner and vertical expansion joints in the wall at specified intervals. This detail is based on the Tile Council of North America (TCNA) method W241.