How to Mount Under Counter Sinks on Quartz Countertops

Installing an undermount sink on quartz countertops can seem daunting, but with proper planning and preparation, it can be a straightforward DIY project. Quartz is an engineered stone that is very durable, stylish, and low maintenance, making it a popular choice for modern kitchen countertops. With the right tools and techniques, you can have a beautiful undermount sink seamlessly integrated into your quartz countertop. This guide will walk you through the entire process step-by-step.

Selecting the Right Sink and Faucet

The first step is choosing the right sink and faucet for your kitchen.

Sink Considerations

When selecting an undermount sink for a quartz countertop, consider the following:

  • Sink dimensions – Measure the existing cutout space in your countertop and choose a sink that will fit within those dimensions. Allow a little extra space for mounting brackets.
  • Sink material – Stainless steel and ceramic sinks are common undermount choices. Stainless offers durability and a modern look. Ceramic provides a smooth, elegant finish but may chip more easily.
  • Number of basins – Single bowl or double bowl? The number and size of basins needed depends on personal preference and space.
  • Depth – Standard undermount sinks have a depth of about 10″, but deeper models are available if more bowl space is desired.
  • Features – Look for options like offset drain placement, accessory trays, ledges, drain grooves etc.

Faucet Considerations

The sink faucet should complement the look and function of the sink. Things to keep in mind when selecting an undermount kitchen faucet:

  • Faucet style – Options like pull-down/pull-out, bridge, commercial style, etc. Pull-down faucets are popular for their convenience.
  • Finish – Should match other fixtures and hardware in the kitchen, like nickel or bronze.
  • Number of handles – Single handle is most common, but some prefer a two-handle classic look.
  • Spout height – Make sure the faucet spout is tall enough to accommodate the depth of the sink.
  • Features – Look for conveniences like 360-degree rotation, magnetic docking, touch-on functionality, a pull-down sprayer, etc.
  • Water efficiency – Models with low-flow options help conserve water.

Once you have selected the perfect sink and faucet combination, it’s time to prepare for installation day.

Preparing for Undermount Sink Installation

Proper planning and preparation will ensure the undermount installation process goes smoothly.

Gather Supplies

Some essential items needed for installing an undermount sink on a quartz countertop:

  • Safety glasses & gloves
  • Tape measure
  • Level
  • Marker
  • Silicone adhesive caulk
  • Rags
  • Denatured alcohol
  • Screws
  • Power drill
  • Undermount sink mounting brackets and hardware
  • Plumber’s putty
  • Silicone sealant

Make sure everything is on hand before starting.

Prepare the Countertop

First, thoroughly clean the countertop area where the sink will be installed. Remove any debris, and clean with denatured alcohol to eliminate dirt and oils.

Use painter’s tape to mark off the sink cutout area on the underside of the countertop. Carefully measure and trace the outline of the sink based on the manufacturer’s specifications.

Tip: It is better for the sink cutout to be slightly smaller than the actual sink dimensions. This allows for small adjustments during installation.

Stage the Sink

Unpack the new sink and set it gently in place on the countertop to test the fit. Make any necessary adjustments to the cutout outline for a perfect fit.

Remove the sink and set aside. Have the faucet and mounting hardware ready to go for installation.

Now the prep work is done, and it’s time to cut the sink opening.

Cutting the Sink Opening

Cutting the hole for an undermount sink requires precision. Quartz is very tough, so specialized tools are needed.

Cutting Options

There are a few options for cutting the sink opening:

  • Quartz fabricator – Hire the installer who fabricated the quartz countertop to come cut the hole for the sink. This is the easiest option but adds to the cost.
  • Handheld quartz cutter – These specialty power tools with diamond-tipped blades can cut quartz. Rent or purchase one just for this project.
  • Angle grinder – A fitted diamond blade can cut quartz with an angle grinder. Keep a pan of water nearby to keep the blade cool.

Cutting Tips

To ensure a clean, smooth cut:

  • Cut just inside the traced sink outline
  • Make gradual cuts, don’t rush through the thickness of the quartz
  • Keep the blade lubricated with water
  • Wear eye and ear protection, as well as a mask
  • Vacuum up debris during the cutting process

Take time with the cut out to get a perfect opening for the sink.

Installing the Sink

Once the sink opening is prepped, it’s time for the fun part – installing the beautiful new undermount sink!

Step 1: Set the Sink

Carefully lower the sink into the opening. Have a helper hold it in place while checking that:

  • The sink is centered within the cutout
  • All edges fully contact the quartz surface
  • It forms a tight seal all around

Make minor adjustments as needed to get the sink positioned just right.

Step 2: Secure Mounting Brackets

With the sink held firmly in place, attach the mounting brackets that came with the sink. Most sinks include 4-6 metal brackets that affix to the underside.

Follow the manufacturer’s instructions to fasten the brackets snugly against the quartz. This provides support and keeps the sink anchored securely.

Step 3: Apply Sealant

Sealing the seam between the sink and countertop is crucial to prevent leaks. Run a smooth, consistent bead of silicone adhesive sealant around the entire seam.

Carefully follow the sealant directions for cure time before proceeding.

Thorough sealing is key to creating a water-tight bond and a flawless finish.

Step 4: Install Plumbing

The sink drain and faucet plumbing can now be installed:

  • Drain – Apply plumber’s putty around the drain hole underside and tighten into place over the sink tailpiece. Connect p-trap.
  • Faucet – Insert water supply lines and secure faucet according to manufacturer instructions.

Make sure all connections are tight.

Step 5: Test for Leaks

After plumbing is complete, test for any leaks:

  • Fill the sink with water and check underneath for drips.
  • Run the faucet and check all connections for leaks.
  • Let sit full overnight and confirm it holds water.

Leak testing is an essential step before completing the job.

Finishing Touches

Once installed properly with no leaks, just a few finishing touches complete the undermount sink installation.

Run Water and Check Functionality

With the water supply on, run the faucet and test out each function. Make sure it operates smoothly and as expected. Also check:

  • Hot and cold water work properly
  • Drainage flows well
  • No additional leaks appear

Address any functionality issues immediately.

Apply Sealant Around Sink Edges

Apply a thin bead of silicone sealant along all edges around the sink where it meets the countertop. Wipe away any excess for a clean finish.

This provides additional protection from moisture and gives a seamless look.

Clean Up the Sink and Counter

Remove any caulk, putty, markings, dust or other residue from the sink and surrounding countertop. Clean the area well using household cleaners.

Proper cleanup leaves the beautiful new undermount sink shining and ready to use!

With some careful planning, the right tools, and attention to detail, an undermount sink can be installed securely on a quartz countertop for years of stylish, trouble-free use.

FAQs About Installing Undermount Sinks on Quartz

Still have some questions about installing an undermount sink in quartz? Here are answers to some frequently asked questions:

Is undermount better than drop-in for quartz?

Yes, undermount installation is best for a seamless look with quartz countertops. The polished rim of a drop-in sink may not sit perfectly flush.

What size is a standard kitchen sink?

The most common size is a 33″ wide single bowl sink. Double bowl sinks typically range from 30″ to 33″ wide.

How thick should quartz be for undermount sink?

A thickness of at least 2 cm is recommended for durability and proper undermount installation.

What screws to use to attach undermount sink?

Use the mounting brackets and screws provided with the sink. Stainless steel brackets with corrosion-resistant screws work best.

Should anything be applied to sink bottom before installing undermount?

Yes, silicone adhesive caulk should be applied evenly to the rim of the quartz opening before lowering in the sink.

Can I install undermount sink myself?

Yes! With proper planning and caution, installing an undermount sink is totally DIY-friendly. Just take it slow and follow all steps.

How long does undermount sink installation take?

Once the countertop is prepped, expect the sink installation process to take 2-3 hours, plus additional time for plumbing, sealant curing, and testing.

Do I need to seal around an undermount sink?

Yes, sealing the seam with silicone adhesive sealant is a must to prevent moisture damage and leaks.

With the right preparation and methods, installing an undermount sink on quartz countertops is an achievable DIY project. Following this step-by-step guide will ensure a secure, watertight installation that seamlessly integrates your sink into the countertop. Take time to get the cutout, positioning, and sealing done perfectly. The end result will be an elegant, durable undermount sink that brings functionality and style to your kitchen.