How to Install a Sink Under Quartz Countertop

Installing a sink under a quartz countertop can seem daunting, but with the right planning and tools it can be a straightforward DIY project. Quartz is an extremely durable and beautiful material that makes a gorgeous countertop, but requires some special considerations when cutting out the hole for an undermount sink. With proper care taken at each step, you can end up with a smooth, seamless installation.

Choose the Right Sink and Countertop

The first step is to select the sink and countertop material. An undermount sink has a rim that sits below the countertop, as opposed to a drop-in sink that sits on top. Make sure to choose an undermount sink designed for a quartz countertop.

When selecting the quartz slab, opt for a thicker material, at least 2 cm. This will provide stability when cutting the hole for the sink. Also pay attention to the edge profile of the quartz, and choose an edge design like a pencil round that will accommodate an undermount sink.

Prepare the Countertop

Once you have the sink and countertop slab, inspect the quartz carefully before cutting to make sure there are no defects around the area for the sink. Cover the countertop with painters tape to reduce chipping when cutting.

Use the sink template to mark the hole placement, accounting for any faucets or soap dispensers. Mark a few inches wider than the template to give yourself some room for error.

Cut the Hole

Cutting the hole in quartz requires special diamond-tipped blades and tools. You can rent a quartz fabricator saw from certain home improvement stores. A straight edge guide can also help make accurate cuts.

Cut very slowly and steadily to get clean edges. Make relief cuts at the corners to avoid cracking the slab. Don’t try to cut the hole with standard tools like a jigsaw, as this can damage quartz.

Secure the Sink

Once the hole is cut, set the sink in place and check the fit. There should be full contact between the bottom sink edge and countertop surface without gaps.

Apply a bead of silicone adhesive around the top rim of the sink where it will adhere to the quartz. Carefully set the sink in place and attach the metal brackets below to hold it securely as the silicone cures.

Finish the Edges

Examine the cut edges of the quartz and use polishing pads to smooth out any small irregularities. This helps prevent cracking or chipping long term.

If the gap between the sink edge and cut quartz is larger than 1/16 inch, use a color-matched quartz filler material to fill it in for a seamless look. Remove any excess silicone and let dry completely.

Questions and Answers

What type of saw should be used to cut the quartz?

It’s best to use a specialized quartz fabricator saw with diamond-tipped blades. This saw is designed to cut quartz cleanly and accurately without cracking or chipping the material. Standard saws like a jigsaw are not suitable.

Can any silicone adhesive be used to install the sink?

No, you’ll want to use a silicone specially formulated for quartz and undermount sinks. Look for one that offers long-term durability without any yellowing over time. Always check compatibility.

Should you install the faucet before or after cutting the quartz?

It’s best to fully install the faucet after cutting the hole for the sink. Trying to cut around an installed faucet creates unnecessary challenges. Just mark where it will go before cutting the hole.

What can be done about small chips on the cut quartz edge?

Using a high quality diamond polishing pad, gently smooth out any small chips or uneven areas along the cut edge of the quartz. Take care not to chip it further. For larger chips, consult a countertop professional.

How long does the silicone need to cure before finishing the installation?

Typically the silicone adhesive will need 24-48 hours to fully cure and adhere the sink to the quartz. After that time, you can complete the installation by caulking around the edges and making any final connections.


Installing an undermount sink in quartz countertops creates a beautiful, seamless look. With careful planning and the right tools and materials, it can absolutely be a DIY project. Pay close attention to choosing the sink and countertop, proper cutting technique, securing the sink, and finishing the cut edges smoothly. Expect the whole process to take some time and care. When done properly though, you’ll end up with a functional and gorgeous modern countertop.