How to Create a Shower Drain in a Concrete Slab

Determine where existing drain lines are installed within or under the concrete and plan the location for the shower and drain. For easier drain implementation, locate the shower drain near an existing drain line.

Turn off any fixtures that send waste or water to the drain line or otherwise ensure that they will not be in use.

Break up the concrete where the drain will be installed. Remove concrete to create a trench between the planned shower drain and existing drain line. Break up concrete in a large enough area around where the shower pipe will connect to the drain line to ensure that it can be worked around easily. Use a jackhammer, concrete saw or sledgehammer to break the concrete. Wear safety glasses, a dust mask, work gloves and ear protection when breaking up concrete.

Remove any gravel or fill from the created trench and around the existing drain line. The installed pipe must have a slope of at least 1/4 inch per foot so that it will force water toward the exit. Make sure that the bottom of the trench reflects this as well as the level at which the shower drain pipe must connect to the main line. The minimum required trench depth will depend on the distance between the drain and the outlet and the depth of the drain line.

Cut out a small section of the drain line using a hacksaw or pipe cutters, depending on the specific pipe material. Remove enough piping to accommodate the fitting that will connect the shower drain pipe to the main drain line.

Attach the fitting to the drain line. Make sure that the pipe ends are clean and free of debris or rough edges. If the fitting is connecting two different pipe materials, take this into account when selecting a fitting or connectors. Remember, when joining plastic to metal, always screw the male plastic connector into the female metal connector. Use an adhesive, thread tape or sealer/lubricant designated for use with the specific pipe material. Some adhesives may require that a primer be applied to the pipe sections first.

Lay out and connect the sections of pipe so that they extend between the main line fitting and the elbow or fitting where the drain piece will be installed. Make sure that the pipe is well-supported and slopes slightly toward the drain line, then glue or screw sections together. Follow directions provided by the specific adhesive or tape manufacturer to ensure that the length of drain pipe is watertight.

Attach the piece of pipe that the drain will be glued into or the drain piece itself to the piping. Before attaching the drain piece, make sure that the height of the concrete that will be poured plus any additional flooring material is taken into account. Do not attach the drain strainer piece yet.

Fill in the space around the pipe with backfill that was removed earlier or gravel. Fill the trench and space around the pipe up to the point that it is ready for the concrete to be poured.

Place an old can or similar object over the drain opening to keep concrete from entering the drain pipe.

Prepare concrete according to manufacturer's instructions and pour it into the trench. Use a trowel to pack mortar in, then run a board or screed over the surface to identify and correct any low or high spots. Finally, run a float over the surface to create a smooth finish. If a rougher finish is desired, wait until the concrete begins to set before touching up the surface with a bristle broom or other finishing tool.

Remove the can from over the drain once the concrete begins to harden.

Cover the new concrete with plastic. Mist the area daily for about a week to allow for proper curing.

Attach the drain or drain strainer piece and otherwise finish the shower floor.