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How to Build a Shower Pan

Palmira S Nov 23, 2018
Are you planning to build a tiled shower base, but don't know your way through? Then, learning how to materialize the plan may help you execute the procedure considerably well. Remember: easy does it!
Learning how to build a shower pan needs careful attention to instructions, and the result can be good if the process is carried out properly.
If built well, it won't leak and will last for a long period of time. Otherwise, it may lead to disasters like wandering water. With a few precautions taken, you can manage to have a successful installation.

Materials Required

  • Drain base
  • Plumbing tools
  • Mortar mix
  • Concrete finishing trowel
  • Backer board
  • Waterproof membrane
  • Chicken wire or wire lath
  • Caulking
  • Caulking gun
  • Roofing felt


  • Make a multilayer solid shower pan using a waterproof membrane and mortar bed.
  • Place the supporting flange on the plywood subfloor.
  • With a thin, latex-modified mortar bed, create a sloping floor. The minimum advised slope for the subfloor is 1/4 inch.
  • Secure the perimeter of the shower floor with float strips of size 3/4 x 3/4 inch, which act as a guide while installing the mortar bed.
  • The water goes out of the shower through the drain. If this gets clogged, water spills from the pan onto the floor. A clamping ring is used where its lower part provides backup drainage, and the upper part works as an ordinary drain. Adjust this ring drain at the subfloor, and nail 3/4 inch float strips around the boundary of the shower floor.
  • Nail the float strips, and cover the plywood subfloor with a layer of roofing felt of thickness 15 lb. Place a layer of galvanized-expanded wire lath above it. They are held together with flat staples.
  • Dig the latex-modified mortar. For shaping the slope, ride over the float strips and the drain flange with a wood float, and pack the mortar with a float.
Before you install the shower pan membrane, keep the sloped mortar in the same condition overnight so that it hardens. The cross section of the deck mud is thin. Hence, use a strength-enhancing-latex additive instead of water when mixing the mortar.

Installing Liners and Blocking

Chlorinated polyethylene (CPE) is used as waterproof liner for the shower base. Install blocking around the perimeter of pan area between the studs. The blocking should extend at least up to one inch above the upturned sides of the pan. Ensure that all the fasteners are flushed and countersunk.

Installing Shower Pan Membrane

Construct the sides according to the local codes. They can be either 8 or 9 inches. Unwind the membrane, cut it, bend the corners, fold up the membrane, and lay it on the shower floor for trial. Unscrew the membrane if it fits well, and place a bead of rubber sealant close to the lower drainage flange.
Place the membrane on the shower floor, fold and crease it. Secure it to the wall-blocking, and place all staples an inch above the top edge. Place the sealants between different levels of corner folds so that the material is held tight against the wall-blocking.

Installing Dam Corners

Prefabricated dam corners are placed at the point, where the shower curb adjoins the upturned pan membrane. Enforce this membrane with two beads of sealant of size 1/8 inch at a distance of ½ inch from each other. With the help of a trowel, bed the dam corners into the sealant.
The fasteners should be placed at the top inch of the upturned edges. If the bolt heads are extending out of the drain, then cut them and cover them with a membrane. Make the bolts tight, and cut a hole for the opening of the pan to the drain.

Testing the Shower Pan

With an expansion-type stopper, plug the drain, and fill the pan with water till it reaches the top of the curb. Drain the water, and install the mortar floor. Draw the drain screen into the body of the clamping ring drain adjusting it with the height of the floor.
You can avoid the deck mud from plugging the weep holes by placing a free draining material like pea gravel around the base of the drain. Allow half of the deck mud to float out, and then place a reinforcing wire which should be covered with the remaining mud. Run a float over the mortar floor for the final slope.


After finishing the mortar bed, the floor tile should be 1/6 or 1/8 inch above the top of the drain. It should be 1/8 to 1/4 inch below the bottom edge of the wall tile. Pass the top front edge of the wood float so that the installed bottom edge will ride along with it.
You can, thus, build a shower pan for yourself according to your taste and requirement. Not only can you build it strong and firm, but you can also prevent unnecessary expenditure. You can give your shower enclosure a personalized look while maintaining the safety and comfort as well.