Home and Garden | Installing a Pedestal Sink - Plumbing

A pedestal sink takes up less floor and wall space than does a vanity unit; it also offers a more modern, stylish look for your bathroom and can even make the room appear larger. Lag screws hold the sink to the wall and the pedestal to the floor (Fig. 1). If you are replacing a vanity unit with a pedestal sink, however, you may need to move your existing water supply lines, add new drywall and finish areas on the wall and floor that were left unfinished and hidden by the vanity. With this in mind, you may want to take this opportunity to redecorate your entire bathroom rather than try to match old, and maybe obscure, colors, patterns, wallpaper or flooring. When installing a pedestal sink use the instructions below as a guideline while following the manufacturer's instructions for specific information and measurements.

PROJECT BASICS

Project: Moderate
Estimated Project Time: 4 hours
Start Tips: You might need a helper to assist you in lifting the old and new sinks.
Safety Tips: When working under the sink, wear safety goggles to protect your eyes from debris.
Recommendation: Do-it-Yourself

TOOLS & MATERIALS

Pedestal sink, faucet and fittings	Copper tubing
P-trap and fittings	Emery cloth, propane torch, solder and flux, as needed
Safety goggles	2 shutoff valves, as needed
Bucket	Length of 2x4 lumber
Measuring tape	Drywall and drywall joint compound, tape, screws or nails
Utility knife	Taping knife
Adjustable pliers	Paint and paint brush, wallpaper and glue, or tiles, adhesive and grout, as needed to finish the wall or floor
Pipe wrench	Spirit level
Adjustable wrench	Plumber's putty
Crowbar	Chrome risers or flexible braided stainless-steel risers, as needed
Hacksaw	Piece of thin cardboard
Screwdriver	Pencil
Drywall saw	Power drill and carbide bit
Length of 2x8 lumber	Silicone caulk
Nails	Caulking gun, as needed
Hammer
Tube cutter

INSTRUCTIONS

1) Take out the old fixture
Turn off the water at the main valve, then turn the knobs on the faucet to drain any water and relieve the pressure in the water lines. Then disconnect the hot and cold water supply lines, the drain arm under the sink and the trap from the sink basin. Use your adjustable pliers or a pipe wrench as needed; put a bucket under the water pipes to catch any water.

If there is a backsplash around the sink, it will have to be removed also. Use a crowbar to pry the backsplash away from the wall or if it's connected to the wall with screws or bolts rather than adhesive, unscrew them or cut them off using your hacksaw.

Look under your countertop for screws or wing nuts that connect the countertop to the wall or the vanity. Remove any screws and wing nuts and your countertop and sink should now be completely free. If not, loosen any remaining connections. Lift the sink and the countertop off the vanity as a single unit. The unit will probably be quite heavy, so you may need some assistance. Unscrew the vanity from the wall and remove it from the bathroom. If the vanity is still in good shape, you may want to sell it at your next garage sale.

Fig. 2

2) Add backer board
A backer board is needed to support the hanger bracket and the mounting bolts of the pedestal sink. Use a drywall saw to cut out the drywall between the studs where your water pipes and drain are located. You will need to remove only the drywall up to the height of your sink. Measure the distance between the studs (probably 12 inches on center) and cut your 2x8 board to that measurement to use as your backer board. Check the manufacturer's instructions for the sink's installation height, then nail the backer board flush against the outside of the wall studs so that the board is at the installation height.

If you're really lucky, you won't have to move your shutoff valves. Chances are, however, that you will. The manufacturer's instructions will specify the height and location for the shutoff valves. Apply the valve stubouts to these specifications so they will stick out of the wall. (Fig. 2)

3) Cover the opening in the wall
Measure the opening in the wall then cut a sheet of drywall to fit this measurement. Cut out holes for the drainpipe and the valve stubouts. You will need to nail some blocks of 2x4 lumber flush against your wall studs to use as a backing for the drywall. Space the blocks every 12 to 16 inches, making sure a block is located at the top and the bottom of the opening, and then nail the blocks to the studs. Using drywall nails or drywall screws, fasten the piece of drywall to the wall. Use a taping knife to apply joint compound and drywall tape to fill the seams where the new drywall butts against the old drywall. Make any necessary repairs to the floor and the wall.

Fig. 3

4) Install the support for the sink
A hanger bracket will need to be secured to the wall at the height specified by the manufacturer. Place your level across the bracket, making sure the bracket is level, then fastening the hanger bracket to the wall using lag screws (Fig. 3). The screws will secure the bracket to the backer board.

Fig. 4

5) Install the shutoff valves
Slide the escutcheon plate over each of the stubouts. Determine how long each stubout needs to protrude from the escutcheon, including the length of the valve compression nut and the valve collar. You may want to add a little extra to your measurement just to be safe; you absolutely do not want the stubouts to be cut too short. Cut each stubout to your measurement using a tube cutter. Slide the valve compression nut and the compression ring onto the stubout. Place the valve collar and shutoff valve over the stub as far as they will go. Screw the compression nut onto the threads of the valve collar. Then using an adjustable wrench, tighten the nut forcing the compression ring onto the supply pipe and against the inside of the valve collar thereby producing a leak-free connection. Do the same on the other stubout.(Fig. 4)

Fig. 5

6) Install the faucet and drain
Apply the gasket, or if your sink does not come with a gasket apply a bead of plumber's putty to the base of the faucet, and then insert the stems of the faucet and the copper waterline tubing through the mounting holes in the sink. Turn the sink over and tighten the mounting (coupling) nuts. You may have to move the tubes around a little to ensure a proper fit. Fasten either chrome risers (supply tubes) or flexible braided stainless-steel supply tubes as needed to the copper tubes by tightening the nuts on the copper tubes with your adjustable wrench. Chrome risers may look better, but they do not offer the flexibility of the braided metal supply tubes. (Fig. 5)

Fig. 6

7) Attach the sink to the wall
Pick up the lavatory and slide it onto the hanger bracket. Look under the sink at the alignment of the drain, trap and water supply tubes (Fig. 6). You may need to remove the sink to make some adjustments to the drainpipe or supply tubes. After making the necessary adjustments, hang the sink on the bracket. Use your adjustable wrench to tighten the compression nuts that connect the water supply risers to the shutoff valves. Move the P-trap on the drain into position between the sink tailpiece and the drain arm in the wall, and then tighten the slip nuts on the P-trap.

8) Install the pedestal
Slide a piece of thin cardboard under the pedestal to protect your floor, then move the pedestal (with the cardboard) into place under the sink. Carefully raise the sink a slight bit so you can move the pedestal into position (Fig. 7). The pedestal will be secured by a lag screw through the bottom of the pedestal and into the floor (see Figure 1). Mark on the floor where the hole in the base of the pedestal is located; pierce a hole in the cardboard so you can make this mark on the floor. (If you have a tile floor, it's best for the hole to go through the grout rather than the actual tile if at all possible.)

Remove the pedestal then drill the hole for the lag screw. Do not drill the hole with the pedestal in place or you could crack the pedestal's base. Slide the pedestal back into place and remove the piece of cardboard. Use your adjustable wrench to tighten the lag screw and washer and secure the pedestal to the floor.

9) Apply caulk Apply a bead of silicone caulk along the edge of the lavatory where it butts against the wall and another bead around the edge of the pedestal where it meets the floor. Take your time applying the caulk. The caulk should be administered evenly and just thick enough to fill the gap.

10) Final inspection
Turn the water back on and open the shutoff valves. Look closely at each of your connections for leaks. If you find a leaks, turn the nut slowly until the leak stops. Open the faucets to make sure the water flows smoothly; a few initial air pockets are normal.

Putting in a Pedestal Sink