How to Install a Bathroom Countertop and Undermount Sinks
Host Amy Matthews shows how to spruce up a vanity by installing a bathroom countertop and undermount sink.
Dry fit the vanity top. In our project, we installed a granite countertop and backsplash from a company specializing in remnants.
If the granite hasn't been pre-cut to accommodate hardware specifications for your vessel sink drain and faucet, measure and cut any required holes in the granite. Use a marker to trace the sink's drain hole onto the countertop, marking the center of the circle (Image 1).
Use a nailset to chip a small amount of material from the granite countertop. This will keep the drill bit from sliding and scratching the granite.
Attach a diamond-tipped hole saw bit to a heavy-duty, corded drill. Cut a piece of sponge approximately the size of the hole saw bit and place it inside the hole saw.
Dip the hole saw in water, then carefully drill a hole at the position marked (Image 2)
Dip the hole saw and sponge in water periodically. This will keep the saw cool and will help lubricate the cut. Remember to keep the saw straight up and down so the hole doesn't tilt to one side. If muscle fatigue makes it hard to control the saw, be sure to take a break and recover.
Repeat the process for the faucet supply lines, as appropriate.
Run a bead of silicone along the top of the cabinet (Image 1).
Set the pre-cut countertop in place (Image 2).
Apply silicone to the back and side splashes and press firmly onto the wall (Image 3).
Run a bead of silicone along the bottom of the sink to prevent water seeping underneath the counter (Image 1).
Drop the faucet water supply lines into the hole in the vessel sink and flip the sink over (Image 2). Secure the faucet mounting nuts to the underside of the countertop.
Seal the surrounding areas of the bottom of the faucet with silicone.
Insert the drain through the drain opening and then through the countertop to ensure a proper fit. Attach the drain assembly following the sink manufacturer's instructions and using the recommended drain hardware. Tighten the nut firmly to hold the sink in place to the counter.
Connect the drain to the P-trap, replacing it if it's old. Reinstall the water supply lines. Use plumber's tape (Teflon tape) to make the connections easier and tighter. Turn on the main water supply, checking the water flow. Inspect for leaks and repair as required.
Remember to use care not to over-tighten any of the hardware around the breakable sink vessel or bowl.