3 common problems; 3 simple solutions.
Time A full day
ComplexityIntermediate
Cost$51–100
Introduction
Wondering how to replace a shower valve when valve access is bad or nonexistent, when the old pipes are galvanized steel, and when you want to go from a two-handle to one handle valve with temperature-balancing and anti-scald features? We show you how to solve these common problems.
If your bath or shower faucet drips, you can fix the old shower valve and faucet with a few inexpensive replacement parts. (If the spout and handles are worn, you can change them out, too.) But if it’s a new style you’re after or features like preset temperatures or anti-scald protection, it’s time for a replacement. How to change shower fixtures and installing a new shower faucet is a straightforward process of connecting the new valve to the old pipes. Sometimes, you only need the manufacturer’s instructions and some basic plumbing know-how. But it isn’t that easy very often. This article will focus on three complications that installation manuals and plumbing books ignore.
- There’s no access to the inside of the wall.
- The old pipes are galvanized steel.
- You want to replace a two-handle faucet with a single-handle model.
Turn Off the Water!
It’s obvious, but it’s worth repeating. Before you start removing an old faucet and installing a new one, you must turn off the water. If you forget that simple step, you could have a very expensive mess on your hands.
Tools Required
- 4-in-1 screwdriver
- Adjustable wrench
- Corded drill
- Drywall saw
- Jigsaw
- Pipe wrench
- Pliers
- Reciprocating saw
- Safety glasses
- Screwdriver
- Soldering torch
- Tape measure
- Tube cutter
Materials Required
- Copper fittings
- New valve
- Pipe joint tape
- Plastic access panel
- Renovation cover plate
- Shutoff valves
Project step-by-step (10)
Step 1
Plumbing Access Panel
To replace a faucet, you have to work inside the wall. Some homes have a removable plumbing access panel in the next room behind the faucet. If you don’t have an access panel, you might be able to replace the faucet by cutting a hole in the shower surround, but the best solution is to install a paintable plastic panel behind the faucet. You’ll find them in various sizes at plumbing suppliers, some home centers or online. Buy a panel that’s at least 14 x 14 inches.
If you don’t want to install a panel because it would be an eyesore, an oversized cover plate inside the shower surround is another option. If you already have an access panel but it’s too low to provide easy access to the faucet, you can install a second panel above the existing one.
Mark the location
Remove the old tub spout or faucet handles. Then, punch a hole into the wall behind the faucet to mark the location of the access panel. Just slip a long screwdriver alongside the tub spout nipple and push. If the wall is plaster rather than drywall, use a drill and a long bit instead of a screwdriver.
Don’t try to position the access hole by taking measurements!
Step 2
Mark the location on the back side wall
Poke a hole from the bathroom side. Don’t try to measure and guess.
Step 3
Cut an access hole
Cut a hole 3 inches smaller than the access panel so you can see the exact pipe locations. Using the access panel frame as a template, mark the full-size hole. Then, cut the full-size access hole.
Step 4
Mount the access panel
After you’ve installed the new faucet, glue the access panel’s frame into place and snap on the cover. You can paint the panel to match the wall.
- Tip: To avoid damaging the panel frame, install it after you’ve replaced the faucet.
Step 5
Galvanized Steel Pipe
Unlike copper or plastic, steel pipes are joined with threaded, screw-together connections. So you can’t simply cut the hot and cold supply pipes. That would remove the threaded ends, and you’d have no reliable way to connect a new pipe.
Disconnect the union fittings
Unscrew the ring nuts that fasten the union fitting to the faucet body. Then, unscrew the union fittings from the supply lines. You can leave the spout nipple connected to the faucet and remove it along with the valve.
Step 6
Cut the shower riser
If the faucet is connected to a showerhead, cut the “shower riser” pipe with a reciprocating saw or jigsaw. Cut slowly and gently so you don’t loosen the connections above. This pipe isn’t under constant pressure, so you can reconnect it with a special coupler later.
Step 7
Add a galvanized pipe coupler
Connect the new faucet. To connect the cutoff shower riser, use a special compression coupler designed for galvanized steel pipe (called a “Dresser” coupling). The coupler won’t work with copper pipe, so screw a short galvanized steel nipple into a copper fitting. For a better seal and easier installation, apply Teflon pipe sealant to the coupler’s threads and rubber seals.
Run the shower and check the coupler for leaks. If you find one, tighten the coupler’s nuts.
Step 8
How to Replace a Two-Handle Shower Valve With a Single-Handle Unit
If you have a two-handle faucet, it’s easiest to replace it with another two-handle model. If you want the convenience of a single handle, you’ll have to hide the two holes left by the handles. An oversized cover plate does just that. Plus, it covers an access hole, possibly allowing you to skip adding an access panel. Remember that replacing a faucet using this smaller hole can be difficult, if not impossible—a large access panel makes the job much easier. You’ll find oversized cover plates (about $23) at plumbing supply stores or online (search for “renovation cover plate”).
Cut the shower surround
Cut a hole for the new valve using a rotary tool equipped with a tile-cutting bit. Mark the cutout using the cover’s paper template and a crayon.
To cut tile, use a rotary tool equipped with a tile-cutting bit. Set the cutting depth of the bit at 1/4 in. and make the first pass. Make more passes, setting the bit 1/4 in. deeper each time until you’ve cut completely through the surround.
If you don’t own a rotary tool, you have a few other options: You can try a jigsaw and ceramic tile blade. These blades cut softer tile well.
If you find that your tile is too hard, use a carbide ceramic tile bit to drill a series of 1/4-in. holes through the tile and wall. Drill the holes close together so there’s little or no space between them. Then, use the ceramic tile jigsaw bit to cut any material between the holes.
Step 9
Install the new valve
Solder in the new valve. Use the paper template to make sure the valve is centered in the cutout.
Step 10
Mount the cover plate
Mount the oversized cover plate. Install the faucet’s standard cover plate over it.
Originally Published: December 03, 2018
