$ 101–250


Preformed, one-piece shower bases make installing a new shower much easier. This article explains the process, from ripping out the old shower or tub to how to install the shower pan and the plumbing.

Tools Required

  • 4-in-1 screwdriver
  • Adjustable wrench
  • Circular saw
  • Corded drill
  • Framing square
  • Hacksaw
  • Hammer
  • Hole saw kit
  • Jigsaw
  • 护膝
  • 等级
  • Miter saw
  • Nut driver
  • 管扳手
  • Reciprocating saw
  • Safety glasses
  • Slip joint pliers
  • 焊接火炬
  • Tape measure
  • Trowel
  • Tube cutter
  • Utility knife

Materials Required

  • 1-1/2英寸。P陷阱
  • 1-1/2英寸。pipe and elbows for waste and vent
  • 1/2-in. copper or CPVC supply lines
  • 1/2-in. plywood
  • 2 x 4s
  • 2-in. screws
  • 2-in. x 1-1/2-in. reducer coupling
  • Mortar mix
  • Shims
  • Shower base
  • Transition couplings
  • washers



Still, setting a base can be challenging, especially when you’re remodeling older plumbing. In this article, we’ll show you how to rip out an old tub and replace it with a one-piece fiberglass shower base. We’ll walk you through the tricky parts, first how to relocate the drain just right, then the necessary venting. Next, we’ll show how to set a rock-solid base—one that won’t crack or leak down the road. Our step-by-step instructions will take you right up to the point where the walls are ready to finish. But we won’t go into those finish details here.


Completing this job—getting the old tub out, reworking the plumbing and installing the new base—will take a Saturday at least, a weekend at most. If you have to run a drain line through joists or studs, we recommend that you rent a 1/2-in. right-angle drill and a 2-in. hole saw (or bit). Otherwise, basic plumbing tools and hand tools are all you’ll need. Be sure to apply for a plumbing permit and have an inspection done at the rough-in stage (when everything is still exposed) and after everything is complete (wall surfaces finished, final hardware installed).


Step 1

Planning the Job

shower base

Start by deciding on the size of the shower base and ordering it. Delivery can take weeks, so don’t rip anything apart until the new one is in hand. If you’re replacing an existing base, simply get one the same size. If you’re replacing a tub with a shower as we did, there are more details to consider. You’ll have the fewest problems if you match the new base to the old tub’s width (the front of the tub to the wall). Go wider if you like, but you may have to replace flooring. Or you may overstep required minimum distances from toilets and sinks. You might have to shift the supply valve as well. Keeping the same tub footprint (or smaller) minimizes the hassles.

We replaced a 5-ft. tub with a fairly spacious 4-ft. base the same width as the tub. We framed a 1-ft.-wide filler wall at the end, which is a nice place to build recessed niches and shelves for shower supplies.

Now’s a good time to buy a new shower valve too, especially if your old one doesn’t have scald protection, as all new ones do. It’s a big project to replace a valve that fails after tile or wall panels are installed.

You’ll need an assortment of pipes and fittings for installing the new drain and for reworking water lines. Pick them up after you open up the floor and walls. At that point, you can see what you need, plan the new drain and water supply runs and make a list of supplies. Make a sketch like Figure A to help you keep track of parts.

Step 2


Figure a shower base

Make a sketch of the project that includes the waste, vent and water supply. Drawing the details will help avoid potential problems and also reduce the number of trips to the hardware store.


There is another (but more costly) option if you’d like to skip all of the extra venting and drain work. Select a shower base that has the drain located at one end, right or left, chosen to match your old tub drain. Select one the same length as the tub and you won’t even need to add filler walls. Since the drain position roughly matches the tub drain, you may not have to add a separate vent, cut out and patch the floor, or reroute the drain line.

Step 3


remove drywall shower upgrade

首先,旋开莲蓬头the bathtub spout. Most styles will unscrew, but some will need persuasion with a pipe wrench. If you want to reuse any parts, wrap the tool jaws with a cloth to prevent damage. Then remove the handle and mixing valve escutcheon cover. Most handles have a little plastic cap that pops off to expose a screw. Remove the screws and pull off the handle and the escutcheon.

Next, strip off the tub surround. Begin by cutting completely through the drywall around the perimeter with a utility knife. If you have cement board behind the tile, simply cut through the tape joint at the ceiling and strip the entire wall. Rip off the tile and drywall together in big chunks. If you have a fiberglass surround with a flange behind the drywall, cut 2 in. outside of the enclosure and pry the sections free one at a time.

Step 4

Disconnect the Plumbing

disconnect the tub plumbing

墙壁打开后,断开管道并关闭主供水阀。通常,您可以从浴缸后面的房间的访问面板或未完成的地下室访问陷阱。如果您无法访问,则必须从浴缸底座后面切一个孔。如果您的关闭阀状况良好,请切断上方的水管。If they’re missing, stuck or corroded, shut off the main supply valve, cut off the water lines and install two compression fitting–style ball valves and leave them in the closed position so you can turn the water back on to the rest of the house. Cover the ends with tape to keep out debris.

Step 5

Remove the Tub

remove the tub

Disconnect the trap from the tub drain, then lift the tub free from the wall. Fiberglass and steel tubs are fairly light, so you can just tip them up and carry them away. If framing makes it difficult to pull out, cut out more drywall along the plumbing wall. Then you can pull the tub away from the wall before you tip it up. Cast iron tubs, on the other hand, are extremely heavy, and we recommend just busting them up with a sledgehammer and carrying out the pieces. (Lay an old blanket over the tub to catch flying shards, and wear safety glasses for this!)

Learn which tools are best for breaking up a cast iron tub.

Step 6

Mark the New Drain

Mark the new drain hole shower install

Snug the new shower base up to the wall studs and mark the drain hole.

Step 7

Cut an Access Slot

cut shower drain access hole

Cut an Access Slot


Step 8

Cut a Path for the Drain

cut a path for the shower drain

开着地板和墙壁,你可以计划你的东北w drain and vent lines. Reworking drain and vent lines will be slightly different with every bathroom, but our photos and Figure A will give you the general idea along with a look at the various fittings you may need.

The two keys for adding a drain are to make sure the horizontal lines slope 1/4 in. for every running foot and that the P-trap opening fallsdirectly在淋浴排水孔下方。首先测量现有排水管中心的高度以及到新排水管的距离。切断旧的P陷阱,然后将排水管运行到新的排水位置。Drill 2-in. holes through the floor joists for the new drain line. Reference marks help you find the drain center later.

Remember to allow 1/4-in.-per-foot slope when you drill holes in joists. Drill 2-in. holes to leave some room to move the 1-1/2-in. pipe up or down to get the necessary slope. But don’t drill in the lower or upper 2 in. of any joist. Most shower drains are designed to receive 2-in. piping, while most existing tub drains are 1-1/2 in. The plumbing code calls for the transition to be made with a reducer directly below the shower, nowhere else.

Step 9

Install the Sanitary Tee

install the sanitary tee

To run the new vent, mark a section of main stack for removal using the 3 x 1-1/2-in. tee (with 6-in.- long nipples) as a guide. Cement 6-in.-long nipples to both ends of a 3 x 1-1/2-in. sanitary tee, then mark and cut the main stack. Join it to the stack with transition couplings.

Step 10

Run the Vent


If your tub didn’t have a vent, you’ll probably have to add one. A local plumbing inspector will tell you the rules (usually within 42 in. of the shower P-trap) when you apply for a permit. The new vent must join the main vent at least 6 in. above any “spill lines” (that usually means sink rims) that share the vent. If your main stack will be plastic, cutting it is easy with a hand or reciprocating saw with an 8-in. blade. If you have cast iron, you’ll have to rent a pipe snapper to make the cut.


Step 11



Cut all the pipes and dry-fit the new vent line and drain line fittings one at a time, working your way toward the P-trap. Begin cementing the parts together. If you’re using PVC, hold the parts together for about 20 seconds after cementing. Otherwise, the parts will “squirt” apart before the solvent cures. Save the P-trap-to-drain-line connection for last. Cement it together, and quickly plumb the P-trap with a 6-in. level before the joint sets.


Step 12

Close the Floor

close the floor install a shower base

Add blocking to bolster unsupported plywood edges and screw a patch to the framing with 1-5/8-in. screws. We added a second layer of 1/2-in. underlayment under the entire shower for a sturdier floor and to better match the finished floor height (1/2-in. backer board and tile). If you need to preserve the original floor height, skip the second layer, but add blocking under the single-layer patch to fully support the shower base.

Step 13

Mount the Mixing Valve and Redo the Supply Lines

run the new supply lines

除非你打算重用的所有面临g supply lines and valves, simply cut out and remove everything and start fresh. Use a hacksaw or a reciprocating saw.

If you’ve chosen a shower base that’s wider than the tub, center the new mixing valve and showerhead over the base. Choose a valve height that’s comfortable to reach and clears any obstacles, and make sure the showerhead lands either above or below the top edge of the shower enclosure or tile. Mount the mixing valve first, following the manufacturer’s instructions, and run new CPVC or copper tubing from the ball valve to the mixing valve and showerhead. Cap the tub spout outlet on the underside of the mixing valve. You’ll need to add blocking to support it.


Step 14

等级the Base and Mark the Studs

level the base and mark the studs shower

水平在所有四个边洗澡基地,匀场where needed. Mark the lip where it abuts studs. Measure, cut and cement the final tailpiece to the P-trap. Take your time. Getting the base level is critical for good drainage. Mark the lip height on the studs and outline the shim locations so you can lift out the base and return it to the exact position. Some bases require that you fit it over a tailpiece when you set it in the mortar.

Step 15

Set the Base in Mortar

set shower base in motar

To set the base, mix up about half a 60-lb. bag of mortar with water to a creamy consistency. Avoid concrete mix; stones in the mix will hold the base away from the floor. Spread the mortar over the floor under the base, about 1 in. or so thick. Then lower the base into the wet mix, forcing it down to the shims and the stud marks. Make sure to push it against the wall. Let it cure overnight. Don’t use the base as a work platform until the next day or you’ll disturb the mortar before it cures. Clamp the base lip to each stud if clamps are included with the unit. Otherwise, clamp it with fender washers and 2-in. screws. Avoid drilling through the lip and screwing the base directly to the studs. The base might crack and leak.

Step 16

Complete the Drain Hookup

shower drain hookup

The new shower stall base will have directions to guide you through the final drain hookup; your drain system may vary from ours. But our shower stall bases directions were to anchor the base to the studs with screws and washers and then push the rubber gasket into place and seat it with a nut driver. Basic directions for how to complete the drain hookup for the new shower stall base are to cut the tailpiece and cement it at the right height. If your drain has a thick rubber gasket, wet it with soapy water and then work it around the tailpiece pipe. Finish seating it by driving it down with a blunt tool.

Step 17


strainer grid

Attach the drain cover to the drain opening.

Step 18

Complete Shower Framing

complete shower framing

Frame the end wall at least 80 in. high for shower doors and curtain rods. Additionally, our base was shorter than the old tub, leaving a void between the wall and the base. We filled in the space with a 2x4 wall. Add backing where the new walls meet existing ones to make the connection solid and for anchoring backer board. And if you leave it short of the ceiling as we did, you can add a convenient built-in shelf.

Step 19


If you're comfortable working with and soldering copper, by all means, go ahead and use it for your water supply lines. We show CPVC plastic fittings because the installation is as simple as cutting and cementing plastic fittings, just as you do with plastic drain and vent lines. To make the transition from copper to CPVC, use compression fittings as shown. You'll find all the CPVC fittings and pipes you need at any hardware store or home center.

Check out the较厚,较薄的铜管的利弊.