Replacing a pedestal sink
with a vanity.

Our vanity base comes in four sizes, each 32″ tall, and each takes a stock vanity sink top:

A stock vanity top is about 1″ wider than its cabinet and ½–1″ deeper. The smallest is 18″ × 16½″ × 32″.

With a stock top on it, the counter stands 32″ plus the top’s thickness. Cultured marble tops are commonly about ¾″ thick (some 1⅛″), and stone tops come in 2 or 3 cm slabs (about ¾″ or 1¼″), so expect the counter at about 32¾″–33¼″.

Choose the size by two things: the stock tops you can buy, and the space in your bathroom. Find the top first, then the base that takes it.

Before you order or build, measure:

• —The width of the space: wall to wall, or to the toilet or tub beside it. Leave room to walk past and to open the door.
• —The depth: from the wall to where the front of the sink top will be.
• —The plumbing: how high the supply valves and the drain come out of the wall, and how far each is from the middle of the space, so they fall inside the cabinet’s open back.
• —The floor: whether the drain comes up through the floor instead of the wall.
• —The top: choose the stock sink top first, and check its size against the base’s.

And the clearances, by the building code (the IRC) and the bath designers’ guidelines (the NKBA):

• —From the toilet: the code asks for at least 15″ from the toilet’s centerline to the side of the vanity, and the NKBA recommends 18″. Either way, make sure you can sit on the toilet without feeling cramped.
• —In front: the code asks for at least 21″ clear in front of the sink and the toilet, and the NKBA recommends 30″.
• —Doors: check that the bathroom door and the vanity’s own doors open without hitting anything.

Turn the water off at the shutoff valves before you disconnect anything.

Our base’s back is open from 6½″ above the floor up to 28½″, across the cabinet’s full inside width (2″ less than its width).

A pedestal sink’s drain usually comes out of the wall about 20–21″ above the floor, with the supply valves at about 24″ (Kohler’s pedestal sheets, for example); a vanity’s are usually a little lower, the drain at about 18–20″ and the supplies at about 20–22″. Either way, they fall inside that opening.

The new sink’s drain won’t sit at the old one’s height, and stock tailpiece extensions from the hardware store make up the difference down to the trap; the plumbing code allows up to 24″ from the sink’s drain outlet to the trap.

Call a plumber when the drain or supply pipes have to move, or the drain comes up through the floor. And if the old shutoff valves won’t close fully, or drip when you turn them, have them replaced before the swap.

Plumbing (supply lines, drains, venting, shutoffs) must be installed to your local code, and we recommend a licensed plumber. A permit may be required.

1. 01Shut off the water, and disconnect the supply lines and the drain.
2. 02Take out the old sink and its pedestal.
3. 03Patch and paint the wall where the sink hung, where the new top won’t cover it.
4. 04Set the base level, and screw its upper back rail to the wall studs.
5. 05Fit the faucet to the sink top, set the top on the base, then connect the supply lines and the drain, and check for leaks.
6. 06Run a bead of silicone where the top meets the wall.

Expect some patching. Flooring is often laid around a pedestal rather than under it, which can leave a bare patch where it stood: check that the vanity covers it. The wall behind a pedestal is often unpainted, with holes from the old sink’s hanger.