How to Convert a Tub to a Walk-In Shower: Demo, Drain, Valve, Kit

Converting a tub to an acrylic shower yourself: $2,490–$3,040 in kit, valve, glass and permit, 24–40 hours.

Before you start

Read the cost comparison first if the method isn’t settled. The short version: an acrylic tub-to-shower conversion saves about $2,235 and is a fair DIY job for someone who can do basic plumbing; a tile shower saves more and is a waterproofing job first; curbless is for a contractor. This guide is the acrylic conversion, with a section on the tile pan at the end.

Two conditions before you commit: the drain is reachable — from a basement or crawl space, or through the floor with a finished ceiling you’re willing to patch — and there’s a second bathroom for the three weekends this takes.

What you need

A base and three-wall kit sized to the alcove, a matched rough-in pressure-balance valve and trim, the 2 in drain assembly for that base, a framed or semi-frameless door, PVC and fittings for the drain and trap, PEX or copper for the supplies, mortar for the base bed, panel adhesive, 100% silicone, cement board or moisture-resistant drywall for the exposed edges, and plywood for subfloor repair. Tools: a reciprocating saw rental for the tub, an oscillating multi-tool, a hole saw, a tubing cutter and push-fit fittings, a drill, a 4 ft level, a respirator and gloves. The priced list is on the cost page.

The two things that decide how it turns out

The drain seal and the base bed. Nearly every leak in a prefab shower is at the drain — a gasket seated wrong, a base that rocks on an unsupported floor and works the seal loose. Mortar bed, level, the manufacturer’s tightening sequence, and a ten-minute test from below.

The valve. It’s code, it’s in the wall forever, and it’s the one part you don’t want to open the panels to reach. Matched rough-in and trim, set at the right depth for the finished wall, tested before the walls close, inspected.

If you’re tiling instead

The demolition and plumbing are the same. Then the floor becomes a shower pan: a pre-slope, a waterproofing membrane with its matched drain, and a 24-hour flood test with the drain plugged and two inches of water — before a single tile. Walls get cement board and the same membrane, the curb is built and wrapped, and only then does the thinset and tile work start. Buy one system and follow its manual; the kitchen backsplash guide covers the tile-setting habits that carry over.

Step by step

1. Plan the kit and pull the permit

   Measure the alcove (a standard tub space is 60×30 or 60×32 in) and buy a base and wall kit that fits it exactly, plus a matched rough-in valve and trim, a 2 in drain assembly for that base, and a door. Apply for the plumbing permit and confirm when the rough-in inspection happens. Turn off the water, drain the lines, and kill the bathroom circuits at the panel.

2. Demolish the tub and surround

   Pull the door or curtain rod, the trim, the spout and handles. Cut the surround and the drywall behind it back to the studs with the multi-tool. Disconnect the drain from below or through the overflow, cut the old supply stubs, and free the tub's flange. A steel or acrylic tub lifts out with two people; a cast-iron tub is cut into pieces in place with a reciprocating saw or a grinder, with a blanket over it and a respirator on. Bag everything for the dump.

3. Inspect and repair what's there

   Probe the subfloor at the drain and along the outside wall; cut out and replace anything soft with matching plywood, screwed to the joists. Check the studs for plumb and flat — shim or plane them, the panels will show every bow. Replace any galvanized supply pipe you can reach. Add blocking between studs where grab bars might go, now, whether or not you install them.

4. Run the drain and set the valve

   Open the floor and reroute the drain to the base's center: 2 in PVC, a 2 in P-trap directly under the drain, sloped 1/4 in per foot to the branch, roughed 1/4 in above the subfloor. Mount the valve on blocking at 38–48 in, plaster guard flush with the finished wall plane, and connect the supplies with push-fit or crimped PEX. Add the shower arm drop-ear elbow at 72–78 in. Cap the valve, pressure-test the supplies, and call for the rough-in inspection.

5. Set the base

   Dry-fit the base over the drain and check level both ways. Install the drain assembly on the base per its instructions — gasket, seal, tightening sequence. Spread a mortar bed where the base's ribs land, set the base, walk it level, and fasten the flange to the studs only where the manufacturer says. Leave it to cure overnight. Seal the drain body to the pipe with the specified solvent or gasket.

6. Install the wall panels

   Dry-fit all panels and mark the valve and arm holes on the plumbing wall; cut them with a hole saw. Back wall first, then the side walls, each sealed to the base flange and to the next panel with 100% silicone, adhesive on the studs behind, screws or clips through the flange. Fit the valve trim and shower head. Then the corner trim or caps the kit provides.

7. Hang the door and caulk

   Install the door frame plumb on the panel flanges per its instructions, with silicone under the sill, and hang the panels. Run a bead of silicone along the base-to-wall joint on the inside, every vertical panel joint, and around the door frame — tooled smooth, not smeared. Let it cure 24 hours before water touches it.

8. Finish, test and close out

   Patch and paint the drywall around the alcove, reinstall the trim, turn the water on and test the valve's temperature limit stop. Run the shower for ten minutes and check the drain from below and every joint for weeping. Fit grab bars into the blocking if wanted. Call for the final inspection, and keep the permit with the house records.

What would this cost you? The walk-in shower calculator prices the DIY version with the tools you already own and a value on your time, next to a pro quote.