Replace a bathroom vanity

Every line shows the quantity to buy and how StudSheet got it: the spacing, the waste and the package size, so you can check it before the supply house or the quote.

In Canada (762 mm vanity)

Set to Canada, the Sheet works the job out again for Ontario: metric sizes, bag sizes, the frost depth and the code notes. It doesn't just convert feet to meters. The first lines:

• 1 vanity, Vanity with top, 762 mm: Cabinet, top and sink in one box. Check the drawers clear the pipes.
• 1 faucet, Bathroom faucet, basic: Match the holes in the top. Most come with their pop-up drain.
• 1 kit, P-trap kit, 1¼ in: The new sink’s drain rarely lines up with the old trap: a new trap and an extension you cut to fit.
• 2 lines, Faucet supply line, braided: Hot and cold for each sink; skip them if the faucet comes with its lines attached.
• 1 tub, Plumber’s putty: Under the drain flange. On a stone top, silicone instead (putty can stain it).
• 1 roll, Thread seal tape (PTFE): For threaded joints only (a threaded stop or drain) — never on compression nuts or slip joints.

1. Shut off the hot and cold stops, open the faucet to let the pressure off, and put a bucket under the trap.
2. Disconnect the supply lines and the trap, cut the caulk, unscrew the vanity from the wall, and lift off the top, then the cabinet.
3. Check the stops and the drain arm: valves that won’t shut or a corroded drain get fixed now (a plumber for old galvanized pipe).
4. Mark the studs; measure the pipes from the wall and the floor, trace them onto the new cabinet’s back and cut neat holes.
5. Set the new vanity: level it, shim it, and screw through the back rail into two studs.
6. Fit the faucet and the drain on the top before it goes on — much easier on a bench.
7. Set the top on a few dabs of silicone; connect the supply lines hand-tight + ¼ turn and the trap, cutting the tailpiece to fit.
8. Turn the water on slowly, check every joint with a paper towel, then fill the sink and let it drain.
9. Caulk: set the backsplash in silicone, then run a bead where it meets the top and the wall.

Must-have tools first, then the ones that help and the ones to rent for the day.

Mistakes that cost a callback or a second trip

• Pipes behind the drawers: Measure the valve and drain heights against the new cabinet’s drawers before you buy.
• Holes too big: Trace from the pipes and cut neat holes; a hole saw makes clean ones.
• Faucet holes that don’t match: Count the holes and the spread in the new top before you buy the faucet.
• The faucet after the top: Fit the faucet and drain on the bench, before the top goes on.
• Cranking compression nuts: Hand-tight + ¼ turn. Plastic slip nuts: hand-tight.
• Not level: Water pools at the back of the top. Level and shim the cabinet.

What the calculator assumes

• Vanity depth about 21″, height about 34″ with the top (typical).
• Drain arm about 18–20″ and stops about 20–22″ off the floor (typical): check yours against the drawers.
• Supply lines: two per sink, 20″ braided; trap: 1¼ in.
• Silicone: about 9 ft at a 3/16″ bead.
• Paid work: many places license plumbers for fixture work too — check the rules where you work before you quote a swap.

The Sheet sets its code notes for the job's state or province. These are New Jersey's and Ontario's; the code reference has more. Always confirm with your building department.

• Room around the fixtures: Codes ask for about 15″ from the center of a toilet or sink to a wall or the next fixture, and 21″ clear in front (IRC R307.1; R327 in the 2024 IRC).

What materials do I need to replace a bathroom vanity?

For the worked example, a 30″ vanity, the Sheet counts 9 lines with waste included, starting with vanity with top, 30″ (1 vanity), bathroom faucet, basic (1 faucet), p-trap kit, 1¼ in (1 kit), faucet supply line, braided (2 lines). Each line's math is in the table above. Put in your own sizes in the vanity calculator and every line is counted again.

How long does it take to replace a bathroom vanity, and can I do it myself?

About 3 to 5 hours for the worked example, in 9 steps. StudSheet stamps it DIY OK: you can do this.

What tools do I need to replace a bathroom vanity?

15 in all. The must-haves start with basin wrench, tongue-and-groove pliers, hacksaw, 4-ft level, stud finder, cordless drill/driver. On the Sheet you mark each one as owned, to buy or to rent.

Stuck while you replace a bathroom vanity? Ask in the Vanities and sinks group of the StudSheet community with this Sheet attached. Homeowners who've done it and verified pros answer, and anyone can read it.

• Plumbing for contractors: run this takeoff at your own prices, send the estimate, and get it signed and the deposit paid.
• Plumbing rough-in (3 fixtures): For plumbers: supply and drain pipe by size, fittings, valves and vents for the fixtures you are adding.
• Water heater replacement (Gas water heater, 4 people): For plumbers: tank or tankless, venting, expansion tank, relief line, connections and the permit.
• Replace a toilet (Toilet, 12″ rough-in): Measure the rough-in, pick a toilet that fits, and swap it with a new seal, bolts and supply line — plus what to do about a broken flange.
• Replace a faucet (Kitchen faucet): A kitchen or bathroom faucet that fits your sink’s holes, new supply lines, the right sealant, and a leak check — or a cartridge for a drip.
• All 45 Sheets, across 16 trades.
• Code reference: frost depths, guard heights, stairs, retaining walls.