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Shower Pans: How to Buy, Install, Fix and Select A Shower Pan

How To Install A Shower Pan


A shower pan is designed to capture the water that collects within a shower. After the plumbing fixtures, it is the most likely component
of a shower stall that you must replace. Installing the shower pan requires meticulous attention to details to ensure that it remains
waterproof and protects the underlying floor from water damage.

The easiest type of shower pan to install is a prefabricated fiberglass design. Select the sturdiest available model within your budget. This ensures that the shower pan won’t leak or crack and allow water to saturate and destroy your drywall or flooring. Spending a little extra money for the shower pan may help you avoid an expensive repair bill in the future.

These steps will help you replace an old and cracked shower pan or install a new unit as part of a home remodeling project.
  1. Purchase a thinset mortar mix that is designed for this application.
  2. Mix a sufficient quantity to coat the area beneath the shower pan. The manufacturer’s instructions will explain the appropriate depth of the mortar.
  3. Cover the drain opening with tape to prevent mortar and other debris from entering the opening. A layer of pea-sized washed gravel will protect the drain’s weep holes.
  4. Use a trowel to spread the mortar evenly within the space.
  5. Gently slope the mortar toward the drain. The slope should match that of the pre-molded shower pan if it doesn’t have a flat bottom. This ensures adequate support under the fiberglass pan.
  6. Once this layer of mortar is dry, install the shower pan liner.
  7. Ensure that the liner extends up the wall approximately two feet. If the front shower stall has a curb, make sure that you cover it.
  8. Overlap the corners to ensure a watertight seal.
  9. Secure the liner in place with galvanized nails.
  10. Apply another layer of thinset mortar on top of the liner and allow it to dry. Ensure that you accurately measure the thickness of the mortar so that you don’t extend beyond the height of the drain pipe.
  11. Attach the drain assembly to the shower pan before you put the pan in place.
  12. Align the pan within the shower stall, and use galvanized screws to secure it to the wall studs. If necessary, build out the studs so that you have a tight fit.
  13. Remove the tape and screw the drain cover in place.

As always make sure you consult the manufacturer instructions with your pan before install in case it differs from what is stated in this guide. Keep reading for an FAQ on shower pan commonly asked questions.

Shower Pans FAQ


What is a flange?
The flange is a barrier that rises between the stud wall and the shower’s backer wall to prevent water from exiting during use.

What is shower pan liner/membrane?
Shower pan membrane is made up of a plastic material and is to be used underneath a bed of mortar and the tile in the shower floor. Shower membranes are used for directing water that seeps through the floor and wall grout to the shower drain.

How do I measure my shower base?
You will want to take a few measurements:
  1. Width: From one stud wall to the other.
  2. Depth: From the front of the curb area to the stud wall in the rear.
  3. The Center of the Drain: Repeat the previous two measurements except start from the middle of the drain to the side wall, then the rear wall.
  4. If you take the first two measurements and subtract ½” from those dimensions you will be able to provide wiggle room for yourself. Subtract ¼” from the last two measurements to do the same.

What are shower pans/bases made from?
Shower pans are usually made from acrylic, tile or marble. Fiberglass, a type of acrylic, is very popular as well. It contains fibers of glass thinly woven in a layer. Acrylic is the most popular type of shower pan. It is plastic and resembles glass due to it being clear.

How do you build shower pans?
Fundamental steps:
  1. You will want to take the shower drain pipe and rough it in.
  2. Prepare your floor and walls for concrete and membrane by cleaning the area.
  3. Install the base of drain.
  4. Lay down a thin layer of concrete to create a slope.
  5. Set down a layer of roofing paper.
  6. Cut and install the membrane and top of drain.
  7. Hang up the concrete board on the walls.
  8. Pour the last layer of concrete with chicken wire embedded.
  9. Build the form for threshold.
  10. Pour the concrete for threshold.
  11. Tile it.

How do you repair a crack in a shower pan?
Basic instructions:
  1. Clean the shower base. You will want to be free of dirt and grime and should use tile cleaner and a scrub brush to do so.
  2. Use sandpaper to smooth over rough cracks.
  3. Fill the crack(s) with polyester filler and smooth the filler with a putty knife.
  4. Let the putty dry overnight.
  5. If the first coat does not fill the crack completely add another coat of polyester filler.
  6. Remove the excess filler and smooth the surface. Use sandpaper to complete both of these tasks.

Instructions for Fiberglass
  1. Use a plastic drop cloth to keep surrounding surfaces clean.
  2. Use coarse sandpaper for sanding the crack(s). Also sand 2 inches or so of the surrounding area.
  3. Buy a fiberglass repair kit. Included should be hardener,fiberglass resin and a mat/cloth.
  4. Cut a patch from the cloth in the kit. It should be slightly smaller than the crack. Make two more patches, each increasingly smaller than the first patch.
  5. Mix the resin and hardener. This should be shown in the repair kit instructions.
  6. The three patches will need to be put into the mix of the hardener and resin. Take out the smallest patch and set it over the crack. Take the other two patches and layer them the same way beginning with the medium size and ending with the biggest piece. Leave the patches to dry for eight hours minimum.
  7. Once the patches are dry, sand them with sandpaper that is 60 or 80- grit. A wet rag should be used to clean the area afterwards.
  8. The plastic filler will need to be placed on the patches. We recommend using a putty knife to complete this task. Be sure it is spread evenly. Use the putty packaging for drying time suggestions.
  9. Mix the filler in the shower pan surface with coarse sandpaper.
  10. Tint the coat of gel so it matches the surface of the shower pan. Please consult the colorant package for color tinting directions.
  11. Apply a layer of thick gel coat by using a paint roller.
  12. Put a plastic wrap on the area and let it sit overnight.
  13. Wet the area with sandpaper that is 220-grit. Wipe it with a wet rag afterwards. Repeat this method by using both 320 and 400-grit sandpaper until the surface is mixed together.

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