How to Install an Undermount Sink in a Granite Countertop

undermount sink in kitchen granite countertop
What You'll Need
Silicone caulk
Undermount sink
Denatured alcohol
Clean cloth
Wing nuts
Masking Tape

Installing an undermount sink is simple. However, installing one of these sinks is slightly more difficult if it’s being done with a granite countertop. While you should get help cutting the granite, you can install the sink yourself by following these steps to save money.

Step 1 – Take Measurements

Measure the sink, so that you know how big the hole in the granite will have to be. You may want the same professional who will cut the hole to measure the sink for you to get the correct dimensions.

Step 2 – Cut the Hole

While you can complete the other steps yourself, it’s best if you hire a professional to cut through granite. This hole will be where you insert the sink. Make sure that the hole’s measurements match the size you need for the undermount sink to sit correctly.

Step 3 – Fit the Sink

Insert the undermount sink into the hole in the granite. The rim of the sink will sit below the granite countertop if it’s the correct size.

Step 4 – Drill Holes

With the undermount sink in place, mark the potions where the holes need to be drilled on the granite countertop. Take the sink out, and use a drill to introduce holes in the marked spots.

Step 5 – Clean the Ridge

Next, clean the ridge with denatured alcohol and allow to dry.

Step 6 – Apply Silicone Sealant

Apply a thin layer of silicone sealant to the sink lip. Then, place the sink in from underneath. Center it into position under the granite.

Step 7 – Clamp the Sink

Place a 2x4 on the countertop across the sink. Then, clamp the sink, with one end going through the sink’s drain hole, and the other end landing on top of the wood plank. Ensure the sink is sitting in the correct position.

Step 8 – Insert the Wing Nuts

Next, insert the wing nuts into the available screw heads. Make sure the nuts are tight. If not, tighten them with your hand.

Step 9 – Install the Fittings

After the wing nuts are in place, stick masking tape to the back of the countertop. Mark the position to make provision for the faucet, and install the fittings after waiting a few days for everything to set. Introduce the faucet and connect the supply lines, as well as any other parts.

Step 10 – Test It

Finally, test the sink. Turn on the water supply to the undermount sink. Check for any leaks.