How to Install a Pedestal Sink

Begin by preparing the workspace. Place a bucket under the existing sink's P-trap to catch residual water. Use an adjustable wrench to turn the hot and cold water shut-off valves clockwise until they are fully closed. Turn on the faucet to release any remaining pressure and water. Use channel-lock pliers or an adjustable wrench to disconnect the hot and cold water supply lines from the shut-off valves. Next, disconnect the P-trap from the sink's tailpiece and the drainpipe in the wall. If there is a vanity, it will need to be removed. Carefully cut the caulk seal along the backsplash and sides with a utility knife. Locate and remove the screws securing the old sink or vanity to the wall. With the help of another person, lift the old sink and vanity away. Thoroughly clean the wall and floor area where the new sink will be installed, removing any old caulk or adhesive.

Before mounting the sink, install the faucet and drain assembly. Place the new sink basin upside down on a soft surface like a towel or cardboard to prevent scratching. Follow the faucet manufacturer's instructions. Typically, you will insert the faucet tailpieces through the holes in the sink basin and secure them from underneath using the provided nuts and washers, tightening with a basin wrench. For the drain, apply a ring of plumber's putty or a silicone bead under the drain flange. Insert the drain body through the drain hole from the top of the sink. From underneath, install the gasket and retaining nut onto the drain body and tighten it securely. Attach the pop-up drain linkage if included. Clean off any excess plumber's putty from the basin.

Determine the final height of the sink (standard is 32-34 inches from the floor to the rim). Place the pedestal in its final location. Carefully set the sink basin on top of the pedestal. Press the sink basin level against the wall. Use a torpedo level to ensure the basin is level both side-to-side and front-to-back. Once level, trace the outline of the back of the sink basin onto the wall with a pencil. Also, mark the locations of the mounting holes through the back of the sink. Set the sink and pedestal aside. Use a stud finder to locate the wood studs behind the marked hole locations. If the holes line up with studs, drill pilot holes appropriately sized for the lag screws provided with the sink. If they do not align with studs, you will need to install a wood cross-brace behind the drywall, which is a more advanced task. For this guide, we assume alignment with studs.

Install the mounting hardware into the pilot holes you drilled. Most sinks use lag screws with washers or specialized hanger bolts. Screw the lag screws into the wall studs, leaving them protruding enough to hang the sink basin on (about 1 to 1.5 inches). With a helper, carefully lift the sink basin and guide the mounting holes onto the protruding lag screws. Thread the washers and nuts onto the lag screws but do not fully tighten them yet. The sink should be supported by the screws but still have some movement.

Carefully slide the pedestal base under the loosely mounted sink basin, aligning it with the bottom of the basin. The pedestal's primary role is support, not bearing the full weight, which is handled by the wall bolts. Check again that the sink basin is level side-to-side and front-to-back using your level. Make any necessary adjustments by slightly moving the sink on the bolts. Once everything is perfectly aligned and level, fully tighten the nuts on the lag screws to secure the sink basin firmly to the wall. Alternate tightening the nuts to apply even pressure. Some pedestals have holes in the base for securing it to the floor with screws; if so, mark these holes, move the pedestal, drill pilot holes, and secure it to the floor.

Now connect the drain plumbing. Attach the P-trap to the sink's drain tailpiece. The P-trap kit will include slip nuts and washers. Ensure the washers are oriented correctly (tapered side towards the threads). Align the other end of the trap with the drain pipe in the wall and connect it. You may need to trim the pipe from the wall or the tailpiece from the sink for a perfect fit, which can be done with a hacksaw or tubing cutter. Hand-tighten all the slip nuts first to ensure proper alignment, then give them a final quarter-turn with channel-lock pliers. Do not over-tighten plastic fittings.

Attach the new flexible water supply lines to the threaded tailpieces of the faucet. Hand-tighten the nuts. Then, connect the other ends of the supply lines to the hot and cold water shut-off valves on the wall. The hot line is typically on the left and the cold on the right. Use two wrenches to tighten these connections: one to hold the shut-off valve steady and the other to tighten the supply line nut. This prevents putting stress on the plumbing in the wall. Tighten until snug.

With all connections made, it's time to test for leaks. Place dry paper towels under all connections (supply lines and drain trap). Slowly turn on the shut-off valves, one at a time, and let the water run. Use a flashlight to carefully inspect every connection point for any sign of dripping. Check the connections at the shut-off valves, at the faucet tailpieces, and all joints of the P-trap. Fill the sink basin completely, then release the pop-up drain to let the water rush out. This pressure-tests the drain connections. If any leaks are found, turn off the water and gently tighten the leaking connection a little more. Once you've confirmed there are no leaks, apply a bead of silicone caulk along the back edge of the sink where it meets the wall and around the base of the pedestal where it meets the floor. This seals gaps and adds stability. Smooth the bead with a wet finger or caulk tool.