How to Replace a Fiberglass Shower

Difficulty: Challenging

Instructions

Things You'll Need:

Shower enclosure, shower pan and shower fixtures
Paint or ceramic tiles
Adjustable wrench, pliers, pry bar
Green drywall or cement backer board
Measuring tape, copper pipe, pipe cutter
Propane torch,solder and flux
Hole saw
Panel adhesive, caulking gun and caulk

Planning for the New Shower Stall

Step 1

Consider the size and configuration for the new shower stall. Are you replacing the existing stall with one of the same size or are you looking to increase the size of your shower? Replacing size for size will likely mean you can use the existing drain and possibly the existing hot and cold water plumbing as well.
Step 2

Changing size or shape of the stall will likely mean you'll have to move the floor drain, and that can involve breaking concrete or the mortar bed of the shower pan.
Step 3

Installing a larger shower stall will require you to do one of two things. Either remove part of a wall to get the stall into the bathroom, or purchase a multi-piece unit that you assemble and install inside the room.

Removing the Old Shower Stall

Step 1

It's best to totally remove the existing shower stall before you try to install the new stall. This will mean removing the existing plumbing fixtures, the drain, the shower wall and shower pan and exposing the existing studs prior to beginning installation.
Step 2

Turn off the water supply to the shower and take down and remove the existing shower doors.
Step 3

Remove the knobs and decorative trim for the existing shower fixtures. Tthis usually involves lifting a decorative cap from the knob to reveal the screw holding the knob on.
Step 4

Detach the shower head pipe by gripping it near the wall and turning in a counterclockwise direction.
Step 5

Lift out the tub strainer by inserting pliers into the crosspieces and turning in a counter- clockwise direction.
Step 6

Underneath the strainer is a threaded pipe called a drain shoe that connects to the drainpipe in the floor. Remove the shoe by turning it counterclockwise.
Step 7

Use a pry bar to remove the wall panels. You should remove any existing tiles or drywall to expose the stud wall.
Step 8

Pry up and remove the existing shower pan.

Installing a New Fiberglass Shower Stall

Step 1

If you are replacing size for size and have chosen a shower pan with a drain placement that supposedly matches the pan you removed, dry fit the pan and check that the hole placement really does line up.
Step 2

If you are going to be moving the drain, chisel out the mortar base and remove the pieces. Put the new shower pan in place and mark on the floor where the new drainpipe needs to be positioned. Remove the shower pan and cut the hole.
Step 3

Install your new drainpipe and P-trap (according to local codes) and run the line back to the main drain.
Step 4

Determine the placement of your hot and cold fixtures and adjust the pipe fittings to line up with the new shower stall. This will likely require cutting into the existing copper pipes, adding new pipe and fixtures and sweat soldering them in place.
Step 5

Install the showerhead pipe. It will require a riser pipe from the hot and cold fixtures that needs to be supported by installing a crosspiece between the studs.
Step 6

Temporarily put the shower pan in place and install the fixture knobs. Drape the walls with plastic and turn the water on to test your plumbing for leaks. If you find any, fix them before going any further.
Step 7

Put insulation between the exposed wall studs to block the noise of the water hitting the walls of the shower from the rest of the house when the new shower is being used.
Step 8

Use a light masonry or mortar mix to build a base for the shower pan (floor). Following manufacturer's directions, install the shower pan and drain. Seal the seam where the pan and drain meet with silicone caulking to prevent any leaks
Step 9

Measure and cut the holes in the walls for the shower fixtures and showerhead (if the holes aren't predrilled). Measure carefully, as you only get one chance to get it right.
Step 10

Prepare the shower wall for installation by applying panel adhesive around the edges of the panels and on the wall studs.
Step 11

Attach the panels, starting at the base and then flexing them onto the wall as you move up.
Step 12

Allow the adhesive to set up and then seal the seams between panels with silicon caulk.

Finishing Up

Step 1

Install green drywall (waterproof) or cement board to the areas above the panels. Leave a 1/8-inch gap between the board and the stall walls. This will be sealed with caulk as part of the finishing.
Step 2

Finish the drywall seams, then paint or install tile as you prefer.
Step 3

Install the door tracks and the doors themselves as per manufacturer directions.
Step 4

Apply silicon caulking along the side and base tracks, the seam between the drywall and the shower stall and between the shower stall and the bathroom floors and wall.