Replacing a bathroom vanity sink isn't as hard as you think. After all, bathroom vanity units can be installed anywhere stop valves and drain lines fit inside. With two to three hours, a few basic skills, and a short list of supplies, you can give your bathroom a whole new look. Our guide for how to replace a bathroom vanity shows you how to install both a single-piece vanity and a drop-in sink.
Installing a bathroom sink in a vanity is made easier by the fact that the supply lines and the drain all remain hidden within a cabinet. If the cabinet has no back, simply attach it to the wall so it encloses the plumbing. If the cabinet has a back, you'll need to measure and cut three holes for the two supply lines and the drain.
First, shut off the water and remove your old sink or double sink vanity. Then find the stop valves and drainpipe. They should be in place and close enough together to be enclosed by the cabinet. If your vanity cabinet has a back (many do not), remove the handles from the stop valves. Then measure and cut holes for the drain and the two supply pipes.
Slide the cabinet into place and check it for level in both directions. If necessary, slip shims under or behind the cabinet. Drive screws through the cabinet framing into wall studs to secure the cabinet.
Set the vanity top upside down on a pair of sawhorses, and install the faucet and vanity sink drain assembly. Check the manufacturer's instructions for details.
Set the top onto the cabinet and check that it is centered. Remove it, apply caulk or adhesive along the top edge of the vanity, and reinstall the top.
Editor's Tip: It typically takes 24 hours for caulk to dry completely, so make sure not to shift the vanity top out of place.
Connect the supply tubes to the stop valves. Then connect the trap.
A drop-in sink—also known as a top-mount sink—is installed on top of a countertop and, like the name implies, drops into a hole on the countertop surface. Drop-in sinks have a rim or lip that sits on top of the countertop, and oftentimes includes pre-drilled holes for the faucet on the back of the sink. Considered one of the most common types of sinks, drop-in sinks are also relatively easy to install. Learn how to install these standard plumbing fixtures below.
To install a drop-in self-rimming sink, first install a laminate countertop or, for a tile countertop, plywood and concrete backerboard. Many sinks come with a template for cutting the countertop. Otherwise, turn the sink upside down on the counter and trace the outline of the rim. Draw a line 3/4 inch inside the first line. Cut this second line with a jig saw.
Apply a bead of bathtub caulk or a rope of plumbers putty around the hole and set the sink. If the sink doesn't have mounting clips, apply a bead of silicone caulk instead of putty. Set the sink in, wipe away the excess caulk, and wait several hours before attaching the plumbing.
Editor's Tip: Look for caulk that is suitable for use around heavy water use. We recomment using caulk that is mold resistent.
If your sink has mounting clips, slip several of them in place and turn them sideways so they grab the underside of the counter. Tighten the screws. Attach the supply lines and the drain trap.