How to Install a Pedestal Sink
Pedestal sinks are an excellent way to change the feel of a bathroom or powder room. They were originally made of enameled cast iron, similar to bathtubs, but in the early part of the twentieth century, they began making them out of vitreous china which is the same material toilets are made out of. While this lowered the cost and the weight of the sink, it also made them a little tricky to install. China is very brittle and can chip or crack easily during installation.
Installing a pedestal sink is not something a novice do it yourselfer may be able to handle alone, especially when it comes to installing water supply lines. Soldering is the typically way to install the water shutoffs under the sink, but you may also use compression style shut offs and avoid soldering altogether.
If you are not very skilled at plumbing projects you may want to hire a professional plumber. But you can save a lot of money by removing the old sink and vanity and only pay the plumber to handle the plumbing part of the project.
Tools and Materials
Hacksaw, for cutting PVC and thick brass pipe
Propane torch, for soldering copper tubing joints
1-foot level, for leveling basin
Water-pump pliers, for gently tightening large nuts on drain pipes
Crescent wrench, for tightening small nuts on compression fittings
Compact tubing cutter, for cutting copper tubing in tight locations
Tubing cutter with reaming blade, for faster cutting on bigger, accessible tubing
Wire brush, for cleaning inside of copper tubing before soldering
Basin wrench, for tightening the nuts on faucet valves and spouts in the virtually inaccessible regions under the sink's basin
Socket wrench, for driving lag screw
Drill and bit, for drilling holes for lag screws
Slotted screwdriver, for attaching lift rod to actuator arm
PVC Cleaner and Solvent
Fine-Grit Sandpaper Roll
Fender Washers and 2 1/2-Inch Lag Screws, Two Each (Screws and washers are not usually included with the pedestal sink)
Spray Water Bottle to put out any smoldering material when soldering
Unlike vanities where all of the plumbing is concealed inside the cabinetry, the drain line needs to be centered on the pedestal of the sink base and the water supply lines should be an equal distance from the center line on either side of the drain stub coming out from the wall.
This may require quite a bit of work including removing drywall or plaster, drilling through studs, and rerouting the copper water lines over to a new location. After all of the new plumbing is completed, the wall will need to be repaired and painted.
It is important to know the dimensions of the sink you are planning to install. After you choose your sink you may want to hire a plumber to rough in a new waste pipe and water lines. Typically the existing waste pipe is too low to install the trap, which fits inside the pedestal.
When the wall is open you should also install blocking to mount the sink top to. The blocking is usually 2 x 6 or 2 x 8 material secured between the studs at basin height. This blocking provides a solid anchor for the lag screws holding the sink against the wall and studs will not line up with the mounting holes in the sink.
1. Rough Plumbing – Water Supply Lines
If you have an existing vanity or sink, you will need to plan on how to remove the fixture before you can work on the new pedestal sink.
Shut off the main water supply and drain the hot and cold lines into a bucket. Disconnect the drain line and clips from the sink basin. Remove the sink, counter top and vanity.
At the sink location, place a bucket under the copper supply lines and, with a compact tubing cutter, shear them both off about 2 inches from the wall. Be careful not to crush the copper pipe; tighten the cutter about one quarter turn after you make 2 revolutions around the pipe.
Locate the distance from the center of the basin's drain to the wall. If you are installing a new sink the dimension is supplied with the instructions. You will need to measure out from the wall and mark this distance on the PVC waste pipe.
2. Rough Plumbing – Drain line
Hold the P-trap, fitted with its elbow, alongside the pipe, with the trap's vertical end centered on the mark and mark the pipe where the PVC shoulder joins the elbow.
With a hacksaw, cut the waste pipe at this mark. To keep the cut square, hold the saw parallel to the wall and do not apply downward pressure.
3. Soldering Supply Lines
Remove the burrs from the copper supply lines with a pocketknife or the triangular blade on a tubing cutter. Polish the ends of the supply lines with sandpaper until the copper is shiny. Coat the line with flux. Polish and flux the inside of the angle stops and slip them, with their escutcheons, over the supply lines. (Note: You may want to install vintage escutcheons that are made of porcelain but you would need to leave the copper lines longer.)
Escutcheon and chrome sleeve
Solder the valves onto the copper lines with a propane torch. Make sure that the valves are opened before you begin. Hold the tip of lead-free solder against the copper tubing where it joins the stop, on the side opposite the flame. The inner tip of the flame should just touch the copper pipe to heat it quickly.
When the solder starts to melt, turn off the torch and run the solder around the joint. After it cools slightly, wipe with a damp rag to smooth the exposed solder and remove any flux. Leaving flux on the copper pipe will cause it to corrode.
4. Installing the Stopper
Following the instructions for the sink, roll some plumber's putty into a ¾-inch-wide rope and wrap it around the pop-up drain, underneath its flange.
Wipe the basin's drain hole clean and drop the pop-up drain through it.
On the underside of the basin, slide a gasket and washer onto the drain. Thread the nut onto the drain and hand tighten. Using a wrench or water-pump pliers, finish tightening with a quarter-turn.
5. Leveling the basin
Set the pedestal on the floor so it lines up with the PVC waste pipe and its center is about the same distance from the wall as the center of the basin's drain. Place the basin on the pedestal making sure it is against the wall. Check the location of the basin and check the level with a torpedo level. You may need to use a wood shim to hold the pedestal and basin in place.
Make a mark on the wall through each of the mounting holes at the back of the basin.
6. Attaching the Trap and Basin
Keeping the pedestal and basin together, move them away from the wall. Have a helper hold the sink steady so it doesn't tip over.
Test-fit the P-trap and elbow assembly to the PVC waste pipe, and measure the distance from the floor to the top of the trap's open vertical end. Mark the same distance up from the floor on the tailpiece of the pop-up waste assembly.
Remove the elbow and place the P-trap's slip-nut and washer over the pop-up waste's tailpiece. Cover the P-trap's threads with pipe dope or plumber's tape and slide the trap up to the mark you just made on the tailpiece. Thread the nut on to the trap by hand.
Tighten the nut with a wrench or water-pump pliers, taking care not to damage the finish.
Drill into the wall where you had previously marked the mounting holes under the basin.
7. Mount the faucet
Place the gasket, if included, or plumber's putty under the flanges of the faucet's valves and spout, and insert them into the holes on the top of the basin.
Slide a gasket and thread a nut onto the underside of each of the fittings. Tighten the nuts by hand, and then finish tightening with a basin wrench. Carefully move the sink back against the wall.
Using a basin wrench to tighten the water line connections of the faucet
Line up the mounting holes in the back of the basin with the holes in the wall. Insert the lag screws with their fender washers through the mounting holes and tighten with a socket wrench while checking for level.
8. Finishing Connections and Testing
Tighten the connection on the elbow and trap. Make sure that the washer is in place. You may want to add some pipe dope the threads before tightening the nut with pump pliers.
For a more finished look you should consider installing chromed copper supply lines from the shut off valves to the base of the faucet. Measure the distance between one angle stop and its faucet valve, add an inch, and cut the tube to length with a tubing cutter.
Slip two compression nuts and a ferrule over the cut end. First, tighten one nut to the stop with a wrench and then carefully bend the supply tube slightly so the head fits into the valve's outlet.
Tighten the head to the valve with the second nut. Repeat for the other angle stop and faucet.
With the lift rod in the up position attach the stopper to the actuator arm, and then secure the arm to the lift rod with the screw provided.
Slide the escutcheon and cover over the PVC waste pipe.
Remove the aerator and filter from the faucet. Turn on the water and partially open one faucet valve. Let the water run for a minute to clear air and any debris. Repeat with the other valve.
With the faucet shut off, check for leaks at all supply connections between the wall and the faucet's valves.
Reattach the aerator and filter.