DIY Network

How to Install a Vanity with Undermount Sink

Licensed contractor Amy Matthews shows how to install a vanity with an undermount sink and faucet.

More in Bathroom

remove old vanity and replace unwanted tiles
  • Time

    Under Half Day

  • Price Range

    $500 - $1,000

  • Difficulty

    Easy to Moderate


Step 1: Prep the Wall

Dry fit the new vanity and mark the holes on the wall for the vanity cabinet anchors.

Tap the marks with a nail punch and a hammer to pre-start the hole (Image 1).

Drill holes for the anchors and move the vanity back in place.

Tap the anchors with a hammer and then tighten with a ratchet or gear wrench (Image 2).

Step 2: Attach the Faucet and Countertop

Attach the faucet to the countertop, threading supply connections through pre-cut holes in the countertop.

Flip the countertop over and apply a 3/8" bead of silicone around the opening on underside of the counter (Image 1). In our project, we used an undermount sink.

Set the sink on the opening and look throughout the drain hole to make sure the sink is centered (Image 2).

Attach the sink clips and lightly tighten with ratchet, taking care not to crack the sink (Image 3).

Flip over the sink and center it on the vanity.

Step 3: Complete the Sink Installation

Underneath the countertop, attach the drain and supply lines. If the P-trap needs replacement, replace with a new assembly. Tighten all connections.

Turn on the water supply lines and check for leaks.

Tip up the counter and sink assembly to apply an even bead of silicone to secure the countertop to the vanity.

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