The Tile Shower Drain - How It Works
The tile shower drain intended for use with a vinyl shower membrane is a four piece drain. Reference Oatey as one manufacturer. A traditional shower pan is built with a sloped concrete base with a waterproof membrane above it. The membrane is topped with a sloped masonry layer which is the base for a layer of thinset and ceramic tile. Read more about shower pan construction at this article.
The tile shower drain catches water from two places. First, most of the water goes through the drain hole in the floor. But the masonry layer above the waterproof membrane is not waterproof. It is soaked with water which over times seeps along the waterproof membrane to drain holes in the drain. These holes are below the surface of the shower floor. A layer of pea gravel over these holes keeps them open.
The four parts of the tile shower drain are:
- strainer
- adjustable drain barrel
- reversible clamping ring
- drain base
The tile shower drain base connects to the trap or trap riser and is securely fastened to the subfloor. Cover the flange of the base with tape to keep it clean.
The 1/4 inch per foot sloped concrete base is poured and shaped to slope just to the edge of the drain base.
The tape is removed and the waterproof membrane is installed over the concrete sloped base. Cut the membrane at the drain just enough to fit over the drain hole with clearance for the bolt holes. Seal the membrane to the drain base with the proper sealant. The clamping ring then goes over the membrane securely joining it to the base.
Determine the final height of the finished floor and screw in the adjustable drain barrel to that height. Put a layer of pea gravel over the weep holes in the clamping ring to keep them free of masonry.
Now the top masonry layer is applied following the slope of the bottom layer. The thickness of the masonry should be about 1 1/2 inches. Remember that the masonry layer should be below the drain height by the thickness of the thinset layer and the thickness of the tile.