How To Install a Pedestal Sink

There are many varieties of pedestal lavatories on the market but they all have one thing in common: they need to be installed correctly.

Lots of contractors and even do-it-yourselfers install pedestal lavatories but fail to provide the proper support.

Strictly speaking, pedestal lavatories function best in powder rooms but most buyers of these beautiful bathroom sinks install them in master bathrooms and kids’ baths as well.

In master bathrooms and kids’ baths the pedestal lavatory takes a lot more use and abuse and that’s where proper support during the installation process comes in. It’s not uncommon for children to reach up and over the rim of the sink placing pressure on the front edge of the fixture. If it’s not properly supported during the installation, it can tip forward and come loose from the wall causing possible water damage, as well as personal injury. In addition, if it can move, the possibility for the porcelain to be damaged increases.

During the rough-in stage, plumb the waste outlet in not more than 22” above the finish floor. On the specifications sheet this is usually labeled “AFF”.

The water stub-outs should be not more than 3” above the 1 ½” waste outlet and not more than 3” to either side. The water stub-outs should be well anchored in the wall and the threaded waste connector should be just inside the finished wall surface.

Note the location of the mount holes on the back side of the pedestal lavatory bowl and install backing material in the wall to correspond with those mount holes. If the wall is finished, remove sufficient sheetrock or lathe and plaster to facilitate installation of the backing material. This backing material can be a piece of plywood inlet into the face of the two nearest studs, or a 2” x 4” or 2” x 6” piece of framing lumber installed between the two nearest studs at the proper height. Make sure you firmly fasten the backing material into the wall with the proper fasteners, either 10d minimum or 12d nails or long wood screws. If you fasten the material with a nail gun, set the nails with a nail set to make sure they are tight.

Install the sheetrock, finish the wall surface, install the trim escutcheons over the waste and water stubs, and install the angle stops on the water stubs. Use a box flange over the waste stub. This is a deep escutcheon.

Next, install the faucet, pop-up drain, p-trap, and wall bend. Then move the pedestal lavatory into place, directing the wall bend into the waste connector. If the floor is wooden, drive screws into the holes in the lavatory base to anchor it to the floor. Be careful not to over tighten the screws or you can break the porcelain base. If you use a screw gun, set the torque to a lower setting, then stop before the screw reaches the base and finish tightening the screws with a screwdriver.

If the floor is a ceramic, marble, cement, etc, mark the holes in the base of the lavatory directly on the floor. Pull the lavatory out, pre-drill the holes and install anchors, if necessary. Reinstall the lavatory, install the proper anchors in the base, hook up the water and waste lines.

Install ¼” lag bolts and washers or other suitable anchors through the holes in the back of the lavatory bowl into the backing in the wall.

Run a bead of acrylic caulk with silicone around the seam where the back of the bowl meets the wall and around the base of the unit and trim it with a wet finger or a caulking tool. Remove the faucet aerator, flush out the water lines, and check the drainage connections for leaks. Double check the operation of the pop-up drain. Sometimes, if the waste is roughed in too high it will interfere with the pop-up linkage. If this happens, you may have to bend the linkage so it will clear the wall bend. Replace the faucet aerator and you’re done!