How to Attach a Sink to a Quartz Countertop

Installing a sink into a quartz countertop can seem daunting, but with the right tools and techniques, it can be a straightforward DIY project. Here is a comprehensive guide on how to attach a sink to a quartz countertop.

Overview of the Process

Attaching a sink to a quartz countertop involves several key steps:

  • Selecting the right sink and faucet for your countertop
  • Making accurate cutouts in the quartz for the sink and faucet
  • Applying silicone adhesive sealant to the underside of the sink
  • Setting the sink correctly into the cutout
  • Securing the sink from underneath using mounting brackets
  • Making sure the sink is level and allowing the adhesive sealant to cure
  • Hooking up the faucet and plumbing
  • Applying silicone sealant around the edges for waterproofing

Properly preparing the quartz and sink, and following best practices for installation, will ensure a durable and water-tight connection for years of use.

Choosing the Right Sink and Faucet

When selecting a sink for a quartz countertop, you’ll want one specifically designed to be undermounted. This means it hangs below the countertop surface, attached from underneath. Undermount sinks provide a seamless, stylish look.

You’ll also want to choose a material like stainless steel or ceramic that is durable, stain-resistant, and easy to clean. Avoid porous materials like concrete that require special cleaning.

For the faucet, opt for a high-quality model with a matching finish to the sink. A single-handle faucet is a popular choice for ease of use. Make sure to get the appropriate size – 8 inches is common for bathroom sinks.

Making the Cutouts

Once you have the sink and faucet, the next step is to make the necessary cutouts in the quartz:

Sink Cutout

  • Use the template provided with the sink to trace the outline onto the underside of the quartz.
  • Make sure the placement lines up with your plumbing.
  • Double check your measurements before cutting.
  • Use a diamond-grit hole saw made for quartz to cut out the sink opening. Go slowly to avoid cracking.
  • Smooth and polish the cut edges with sandpaper.

Faucet Holes

  • Mark the faucet hole locations based on the distances in the instructions.
  • Drill a pilot hole before using a hole saw to cut the faucet holes.
  • Open them up gradually by using hole saws of increasing size.
  • Polish and deburr the faucet holes after cutting.

Applying Silicone Sealant

Before setting the sink in place, you’ll want to lay down a thick bead of silicone adhesive sealant along the rim where it will adhere to the quartz:

  • Run a continuous line around the sink edge, about 1/2 inch from the outer rim.
  • Apply sealant to the outer edge too, for maximal bonding.
  • Use 100% silicone sealant designed for bath and kitchen use.
  • Ensure the quartz surface is clean before applying sealant.

Mounting the Sink

With sealant applied, you’re ready to set the sink:

  • Carefully lower the sink into the opening in the quartz. Do not drop or bang the sink.
  • Make sure the sink rim has continuous contact with the sealant.
  • From underneath, install the metal mounting brackets and tighten to secure the sink.
  • Alternately tighten opposing brackets to ensure even attachment.
  • Check for level on all sides using a small spirit level.
  • Clean up any squeeze-out of excess sealant with a putty knife.

Allowing the Sealant to Cure

Once mounted, do not use the sink for 12-24 hours to allow the silicone adhesive sealant to fully cure and harden:

  • Overnight cure time enables maximum bonding strength.
  • Prevent disturbance of the sink and avoid putting weight on it.
  • The sealant will skin over and become tack-free in about an hour.
  • Full drying time is approximately 24 hours. Adhere to this for best results.
  • Cure time depends on humidity, temperature, and sealant used.

Hooking Up Plumbing and Faucet

With the sink solidly attached, complete the job by hooking up the drain and faucet:

  • Connect the sink drain assembly to the drain pipe, ensuring a tight seal.
  • Attach supply lines from the water supply to the faucet.
  • Run clear water through to check for leaks and verify proper drainage.
  • Caulk around faucet holes if needed to prevent moisture intrusion.
  • Apply plumber’s putty beneath the faucet base before mounting it.
  • Secure the faucet according to the manufacturer’s instructions.

Sealing with Silicone Caulk

The final step is to seal the seam between the sink edge and countertop:

  • Run a bead of silicone caulk around the entire sink rim where it meets the quartz.
  • Smooth the caulk with a wet finger for a clean finish.
  • Remove any excess caulk with a plastic scraper.
  • Allow the caulk to fully cure per the manufacturer’s directions.
  • A quality silicone caulk provides a watertight seal to prevent leaks.
  • Reapply caulk periodically if cracks or gaps appear.

Thoroughly cleaning the area first and allowing proper cure time for all adhesives are key to a long-lasting waterproof connection. Follow the steps above correctly, and your undermount sink will provide years of trouble-free use.

FAQs About Attaching a Sink to Quartz

How long does it take for silicone to dry when attaching a sink?

Silicone sealant takes 24 hours to fully cure. It will be dry to the touch in 1-2 hours but needs a full 24 to reach maximum strength and water resistance.

What is the best adhesive for attaching a sink?

100% silicone adhesive sealant specifically formulated for bath and kitchen use provides the best bond and waterproof seal when attaching a sink.

Can you attach an undermount sink to laminate countertops?

Undermount sinks require a solid surface like quartz, granite, or natural stone. Laminate countertops are not suitable for undermount sink installation.

What screws do you use to attach a sink to quartz?

Brass or stainless steel sink mounting brackets with large-head screws work best to firmly attach an undermount sink without cracking the quartz.

Should I caulk around a sink attached to quartz?

Yes, apply a bead of silicone caulk around the entire perimeter of the sink where it meets the quartz. This waterproofs the seam and prevents leaks.

How do you cut a quartz countertop for an undermount sink?

Use a specialized quartz hole saw or diamond-grit hole saw. Cut slowly and smoothly following a template outline. Smooth cut edges with sandpaper.


Installing an undermount sink into quartz countertops provides a seamless, stylish look for a contemporary kitchen. With the right preparation and methodical installation process, it can be successfully completed as a DIY project. The key steps include precise cutouts using specialty blades, ample silicone adhesive sealant, proper sink mounting and leveling, careful plumbing hookup, and thorough caulking. Allowing adequate cure time for adhesives is also essential. Follow these guidelines carefully, and you can expect lasting performance from your new undermount sink.