How to Replace a Fully Enclosed Shower

Select a pre-made shower with appropriate dimensions to maneuver into a bath space. Measure the bathroom and surrounding rooms to ensure you can carry it through doorways and hallways to get into the space. Opt to tile a shower or use a bathtub with surrounding acrylic wall panels if space is tight.

Disconnect all plumbing and electricity in the bath area. Remove the shower door and any metal tracking. Dismantle the existing shower or shower-tub combo by using a pry bar. Cut the shower unit with a circular saw to dismantle it into two or three pieces, if necessary. Pull loose all shower framework that has deteriorated.

Rebuild the wall framework and plywood subflooring to hold a new shower. Cut new plywood with a jigsaw to fit over floor joists. Create a seamless fit by using the same thickness of plywood for new sections that will replace damaged subflooring.

Install shower framing to enclose a new shower shape, or rebuild the existing shower size if this works better. Create the framing by nailing a top plate around the ceiling perimeter and bottom plate around the floor perimeter. Connect the plates with studs on 16-inch centers. Enclose three framed walls, leaving one wall open with no studs for the shower door. Build one of the framed walls as a wet wall, which will contain all water pipes and drains.

Build the shower framing by cutting 1-by-4-inch boards with a circular saw for the top and bottom perimeter plates. Secure these plates to ceiling and floor joists with 4-inch screws. Use 1-by-6-inch boards for the top and bottom plates on the wet wall, so the deeper wall can support the pipes and drains. Install 2-by-4-inch studs to join the shower top and bottom plates on two sides, but use 2-by-6-inch studs on the wet wall.

Cut holes for drains or water lines with a hole saw in the wet wall plates and studs. Run plumbing both vertically and horizontally through the wet wall framing. Do not build the wet wall from 2-by-4-inch framework, because that will not provide adequately wood to support the plumbing materials. Add fiberglass roll insulation between wall studs on any exterior house walls. Roll this same type of insulation between floor joists as well, if the shower is over a basement or crawlspace.

Follow the manufacturer’s guidelines to install a pre-made shower unit. Secure the shower's flange area to framework with screws. Ensure that all edges of the shower and the base are level in every respect before tightening the screws. Place wood shims where needed to make the unit level.

Cut sections of backerboard to cover shower framework, if you plan to tile the shower interior instead of installing a pre-made shower unit. Install backerboard as a water-resistant underlayment for ceramic tiles. Prepare the shower floor for tiling by lining the floor with roofing felt. Apply mortar mix with a trowel to cover the felt. Cover the mortar mix with screed board, which you will level to prepare the shower floor area for tile. Slope the screed board toward the drain before applying any tile.

Add finishing touches to the bathroom and shower space. Redo the floor with sheet vinyl or tiles to correct any gaps or floor damage caused by the new shower remodel. Install a new glass walk-in door or sliding door to complete the shower enclosure.