06.110.0421: Tile Shower Assembly - Metal Studs, CBU Backing, Bonded Waterproof Membrane, Two-Stage Drain
This detail shows a tiled shower assembly based on TCNA method B421. It illustrates metal stud backing, cement backer board keyed into the mortar bed at the base and fastened to the studs beginning 3 inches above top of finished curb, minimum. It shows a floated curb pitched 1/4″ toward the shower, and a mortar bed with 1/4″ per foot slope to drain. A topical bonded waterproof membrane ties into a two-stage drain with weep protection. The shower walls include an optional vapor retarder membrane. The tile finish is adhered to the shower floor, curb, and walls with a bond coat of modified thinset cement mortar.