How to Plumb a Pedestal SinkUpdated: Feb. 22, 2023
We show you every gritty step—start to finish
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Pedestal sinks present unique challenges
Replacing your old vanity cabinet with a pedestal sink is one of the quickest and easiest ways to remodel a bathroom (Photo). But we should warn you—pedestal sinks can be tricky to put in, even for pros. Often the pipes aren’t in the right spot, making it difficult to fit the pedestal in place and connect the pipes so they look nice. You may discover that there’s no floor tile underneath the vanity cabinet so you’ll have to patch or replace the floor. And you may also have to patch missing baseboard.
In the following article, we’ll show you how to handle the most common problems, including how to relocate your drain and water pipes for a neater installation.
You’ll be able to install a new pedestal sink and faucet in a day even with no previous experience. If you have to relocate the pipes, plan to spend a few more days to move the pipes and patch and paint the wall. For this you’ll need basic plumbing skills like soldering copper and cutting and gluing plastic pipe.
For a complete listing of the tools and materials you’ll need, see “Tools and Supplies” below. And be sure to contact your building inspections department to see whether a permit is required for this plumbing work.
Tools and supplies
Large slip joint pliers
Hacksaw with fine-tooth blade
Close-quarters tubing cutter
Drill and bits
5/16-in. masonry bit
Soldering tools and supplies: Propane or Mapp gas tank with regulator Lead-free solder Flux Wire brush for 1/2-in. fittings Emery cloth Heat shield cloth Leather gloves 10-ft. length of 1/2-in. copper pipe 1/2-in. copper elbows, couplings and caps
PVC pipe tools and supplies: Fine-tooth saw PVC glue PVC primer 1-1/2 in. PVC pipe PVC 45- or 90-degree elbows PVC sanitary tee Transition couplings Organic vapor respirator
Other tools: Reciprocating saw and metal-cutting blade Circular saw Drywall keyhole saw
Note: You can download a copy of this list from the Additional information below.
Step 1: Tear out the old vanity
Photo 1: Disconnect the pipes and remove the old sink
Shut off the water at the main shutoff valve. Remove the trap by unscrewing the slip nuts and pulling it down. Cut the tubes that supply water to the faucet with a hacksaw or tubing cutter or loosen the nuts and pull them out. Lift off the vanity top and remove the vanity cabinet.
Photo 2: Cut open the wall
Cut out the drywall (or plaster) to expose the plumbing and allow access for installing wood backing. Cut along the edge of the studs. Caution: Keep your saw blade shallow to avoid hitting electrical wires.
Tear out the old sink and vanity (Photo 1) and check the drain and supply pipe locations. Pedestal sinks look best if the drain and supply pipes are centered and partially hidden by the sink. Your new sink will come with wall measurements showing ideal plumbing locations.
To be absolutely sure, position the pedestal sink and loosely install your new faucet, pop-up drain and P-trap. Now measure from the floor to find the drain height and determine the best location to put the water supply valves mostly out of sight. Our old drain was 6 in. off center and a few inches too low. The water pipes also were in the wrong spot.
Pedestal sinks look best if you shift the plumbing. If you have to relocate pipes, start by removing a section of wall covering wide enough so you can move the pipes and install wood backing (Photo 2). This means wall repair and repainting later. Use a keyhole saw to cut the drywall (Photo 2), but keep the saw blade shallow to avoid hitting wiring or pipes.
Tip: It’s easier to cut along the edge of the studs and add 2×2 drywall nailers alongside the studs later than to try to cut down the middle of the studs.
Step 2: Replumb the drain and water supply pipes
Photo 4: Mark the new pipe locations
Mark the new height of the drain and water supply pipes on a stud. Mark the new center of the sink on the bottom plate.
Photo 5: Connect new to old with transition couplings
Connect the 1-1/2 in. steel drainpipe to a PVC street elbow with a transition coupling. Tighten the clamps with a 5/16-in. nut driver or socket wrench. Cut the copper water pipes with a close-quarters tubing cutter.
Photo 6: Reroute the drain
Cut the lengths of PVC pipe so that the drain opening in the sanitary tee is centered on the center marks for the drain. Prime the pipe ends and the inside of the fittings. Then spread PVC adhesive on the primed surfaces and quickly assemble each joint, twisting the pipe about a quarter turn as you push it into the fitting. Hold it tightly about 45 seconds.
Photo 7: Reroute the supply lines
Assemble the copper supply lines. Cut, clean and solder the copper tubes and fittings. Support the stub-outs with straps and solder a cap on each. Then turn on the water and check for leaks.
Photo 8: Install sink and drywall backers
Screw a 2×6 to the studs to provide support for the pedestal sink. Screw additional 2×2 backing to support drywall edges.
Photo 9: Close up the wall
Cut drywall and fasten it to the studs with 1-1/4 in. drywall screws. Cover the seams with drywall tape embedded in a layer of joint compound. Trowel on at least two more layers, allowing each to dry before recoating. Use a 10- or 12-in. trowel for the final coat to create a tapered patch. Sand with 100-grit drywall sanding paper. Prime and paint the wall and nail up the baseboard before installing the new sink.
Cutting steel pipes like ours is a real chore with a hacksaw. Rent or borrow a reciprocating saw (Photo 3) to speed up the job. Plastic pipes are easy to cut with any fine-tooth saw. To connect PVC (white) plastic drainpipes to either ABS (black) plastic, copper or steel, use transition couplings (Photo 5). Transition couplings have a rubber gasket surrounded by a steel sleeve with screw clamps at each end. Don’t confuse them with the solid rubber or rippled steel collar types. Transition couplings are available at home centers and plumbing supply stores. Match the transition coupling to the pipe size. If your old pipes are PVC, then you’re set to go; just prime them and glue the new PVC fittings on.
Plastic pipe makes quick work of relocating your drain. Cut and assemble the drain and vent pipes as shown in Photos 5 and 6. Don’t worry if you make a mistake; it’s easy to fix. Just cut the pipe and join a new section with a PVC coupling.
Begin by clamping elbows to the transition couplings on the drain and vent pipes. Then start at the drain and work up toward the sanitary tee, making sure to center the sanitary tee on the new sink location and at the right height. Complete the drain by flexing the PVC drain assembly just enough to glue in the last section of pipe (Photo 6).
We’ve run both the drain and vent pipes at a 45-degree angle for optimal performance. If you’re moving the pipes very far, you might have to use 90-degree elbows instead. Keep in mind that your vent pipe shouldn’t run horizontally unless it’s at least 6 in. above the “spill line” of the sink, or about 42 in. above the floor. Leave the drain stub unglued until the drywall is finished. Then cut the stub so the trap adapter fits snug to the drywall and glue them all together (shown completed in Photo 10).
To secure the copper pipes and help hold them in place as you solder them, level and screw a scrap of wood between the studs and mark the pipe locations on it. Cut the copper pipe and solder the fittings together (Photo 7). Leave about 6 in. of copper pipe sticking out and solder on a cap so you can turn the water on to test for leaks. When the wall patching and painting is done, install the new shutoff valves (Photo 10).
Screw wood backing to the studs to support the edges of the drywall (Photo 8). Measure the sink for the location of the anchors and screw wood backing between the studs in this area (Photo 8). If your work requires a permit, call for a plumbing inspection before closing the wall.
Step 3: Install the new sink
Photo 10: Add shutoffs and adapters
Glue a short length of pipe and a trap adapter to the sanitary tee inside the wall. Then close the main water valve and use a tubing cutter to cut the copper pipes, leaving 2 in. exposed. Slide the decorative escutcheon (for this project you’ll need two 1/2-in. escutcheon), nut and brass ferrule over the pipe stub and attach a compression-type shutoff valve. Hold the valve body with one wrench while you tighten the compression nut with another.
Photo 11: Mark the sink mounting holes
Mark the center of the sink on masking tape stuck to the floor. Align the center of the pedestal with this mark. Set the sink bowl on the pedestal, and lay a 2-ft. level across it. Place small self-adhesive foam or rubber cushions between the bowl and pedestal to level the bowl. Mark the center of the mounting holes on the wall and floor. Remove the bowl and pedestal and set them aside.
Photo 12: Mount the hanger bolts
Drill 3/16-in. pilot holes into the wall at the mounting bolt locations. Tighten two 5/16-in. nuts against each other on the hanger bolts to provide a grip for the wrench. Screw the hanger bolts in, leaving just enough bolt exposed to extend through the sink mounting hole plus 3/8 in. Use a 5/16-in. masonry bit to drill a clearance hole in the tile floor for the 1/4 x 2-in. pedestal mounting screw. The screw will slip through this hole and screw into the wood subfloor.
Photo 13: Mount the faucet
Attach the faucet parts to the sink according to the instructions provided. The manufacturer of our faucet specified a bead of plumber’s putty under the valves and spout to seal them to the sink.
Photo 14: Add the drain assembly
Install the pop-up drain assembly. Press a pencil-width bead of plumber’s putty under the rim of the drain before you press the drain down into the opening in the sink. Screw this piece to the assembly that mounts under the sink. Assemble the rest of the parts and adjust the opening and closing of the stopper according to the instructions. Coat the fine threads on the tailpiece with thread sealant and screw the tailpiece into the pop-up assembly.
Photo 15: Install the sink
Screw the pedestal base to the floor. Slide the sink over the mounting bolts and install a stainless steel fender washer and acorn nut to secure it. Be careful not to overtighten the nut or you could break the sink.
Photo 16: Cut the supply tubes
Mark the supply tubes and cut them with a tubing cutter. Bend them to fit and connect them to the valve and faucet with the nut and brass ferrule provided.
Photo 17: Connect the drain
Complete the installation by connecting the 1-1/4 in. trap assembly to the sink tailpiece and PVC trap adapter. Use a fine-tooth hacksaw blade to cut the trap arm to length if necessary. The arm should extend about 2 in. into the trap adapter. Hand-tighten the slip joint connectors. Then tighten an additional quarter turn with a large slip joint pliers. Cover the trap adapter with a special deep escutcheon (extra deep, p-trap diameter), available at most full-service hardware stores.
With the prep work done, you can mount the sink in about three hours. Here’s how. First, install the valves, drain stub and sink mounting bolts (Photos 10 – 12). Next follow the faucet directions to install the faucet and pop-up drain on the sink (Photos 13 and 14). Finally, mount the sink and connect the plumbing (Photos 15 – 17).
When you set the sink on the pedestal to mark the mounting holes, don’t be surprised if it’s a little tippy—they’re not always perfect. Slide plastic shims under the pedestal if necessary to keep it from rocking, and stick foam pads or rubber cabinet door bumpers under the sink bowl to level it before marking the wall and floor for the mounting screws (Photo 11). When the installation is done, fill the gaps at the floor and between the pedestal and bowl with silicone caulk that matches the sink.
Making the final connection between the faucet and valve can be tricky. If you’re having trouble fitting the supply tube into the valve (Photo 16), loosen the valve (reverse the procedure shown in Photo 10) and swivel it to allow clearance to insert the tube. Then retighten the connection. Always use two wrenches to tighten compression fittings, one to hold the valve and the other to tighten the nut.
Complete the sink installation by installing the P-trap assembly (Photo 17). Hand-tighten the slip joints. Then give them an extra quarter turn with a large slip joint pliers. This is a tight spot to work—ideally, your plumbing is lined up just right so you can finish before your neck cramps up!
Double-check all your connections. Fill the bowl with water. Then let it out and watch for leaks. Tighten leaky joints. If this doesn’t work, you’ll have to take apart the leaky joint and make sure the rubber slip joint gaskets are in place and the brass ferrules on the compression fittings are squarely seated.
Shopping for pedestal sinks
Before pedestal sinks became popular again, you had to scrounge around the salvage yards to find one, but today you’ll find half a dozen styles in stock at most home centers, and dozens more in manufacturers’ catalogs. The sinks are 20 to 30 in. wide and cost about $70 to more than $700. First pick out a faucet. Then buy a sink with holes to match the faucet.
You’ll need a few additional parts and supplies. Buy a 1-1/4 in. 17-gauge chrome-plated trap assembly to connect the drain. The metal pipe cover (escutcheon) that comes with the trap is too shallow to cover the PVC trap adapter and nut we’ll be installing, so buy an extra-deep (p-trap diameter) escutcheon (Photo 17). If you don’t have them already, buy two shutoff valves. Buy valves with a compression fitting to tighten onto 1/2-in. copper pipe (Photo 10) or valves with pipe threads if you’re connecting to the old threaded iron pipes. Buy faucet supply tubes to match your faucet. If your faucet has “pigtails” like ours that are too short, buy two 3/8-in. outside diameter extension tubes (Photo 16).
Many faucets have no tubes attached. For these, buy standard faucet supply tubes. The rigid chrome-plated ones like the ones we’re using look the best, but flexible braided stainless tubes are much easier to hook up. Buy a small container of plumber’s putty (Photo 13) and thread sealant for the sink tailpiece (Photo 14). All these plumbing supplies are available at home centers and full-service hardware stores. Pedestal sink mounting systems vary. Read the directions included with your sink to find out what you need.
Required Tools for this Project
You can download a copy of the Tools and Supplies List from the additional information.
Required Materials for this Project
Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.
- Pedestal sink
- Pipe thread sealant
- Plumber's putty
- Shut-off valves (2)
- Supply tubes (2)
- Trap adapter