Shower Pan Building Materials

Base Building Materials

• The shower pan must be built on and framed by a secure and solid base. Before building paper and metal lath for the pre-pan can be placed, three 2-by-4s must be cut to fit and nailed to floor joists and wall studs at the shower threshold using 16d galvanized nails to create the curb for the pan. Two-by-10s must be cut to fit and installed into the stud bays around the shower perimeter. Fifteen-pound building, tar or felt paper should be stapled to the subfloor.

Mortaring and Reinforcement

• A shower pan built on-site generally consists of at least one and often multiple mortar layers. For the mortar bed and pre-pan, use a thinset mortar mixed to have a fairly dry consistency. It may be ideal to use a polymer admixture to increase the strength of the mortar. Metal lath should be attached to the subfloor atop building paper before the mortar pre-pan is created. A layer of waterproof membrane must be installed atop the the mortar pre-pan before the mortar bed is created. A second layer of metal lath should be cut to size and placed about halfway through the mortar bed.

Drain Considerations

• A shower pan must utilize a shower drain, a three-piece drain that differs from standard fixture drains. The bottom drain piece is glued into the drain opening using PVC cement after building paper is placed. Once waterproof membrane is adhered to the mortar pre-pan, the middle drain piece is bolted to the bottom piece. These bolts must be tightened with a socket wrench or another suitable tool to create a watertight seal. The third drain piece is attached and adjusted to reflect the planned mortar bed depth.

Finishing Materials

• Once the sloped pre-pan, waterproof membrane and reinforced mortar bed have been completed, the pan can be surfaced and finished. In many cases, tiles are applied to the pan surface and attached using a thin layer of mortar. Grout is utilized to fill in the spaces between tiles and the tiles are cleaned and treated with a sealant. Finally, silicone caulk is applied in a thin bead to all joints.

Tools Required

• Several tools will be required throughout the shower pan construction process. A hammer and staple gun with staples will be utilized multiple times. A level, measuring tape, utility knife, metal cutting tool and carpenter's pencil or marker are also extremely important. A trowel and wooden float are required to work with mortar and create a smooth finish. If tiles are used for the surfacing, a tile cutters or scoring tool will likely be necessary to achieve correct tile size for the curb and edges.