How to Apply Base for Quartz Countertops

Installing quartz countertops can add beauty and value to your home. A key step is properly applying the base that the quartz will be installed on top of. With the right materials and techniques, you can create a smooth, even base for flawless quartz counters.


Quartz countertops are popular in kitchens and baths because they are low maintenance, durable, and come in beautiful colors and patterns. While quartz itself is resistant to stains, scratches, and heat, it needs a properly prepared base for successful installation. Taking the time to apply the base correctly will ensure your countertops last for many years.

What You’ll Need

  • Tape measure
  • Level
  • Plywood or particle board
  • Shims
  • Construction adhesive
  • Screws
  • Caulk/silicone

Preparing the Cabinets

Before applying the base, make sure your cabinets are ready.

  • Clean cabinets so they are free of dust, oils, or debris
  • Make any needed repairs – tighten loose hinges, replace broken parts
  • Ensure cabinets are level and plumb using a level
  • Adjust cabinets if needed by tightening legs or adding shims

Level and plumb cabinets provide the proper foundation for installing the countertop base.

Measuring and Cutting the Base

Once cabinets are prepped, the next step is measuring and cutting the base.

  • Use a tape measure to find the length and depth measurements for each section of countertop
  • Transfer measurements to plywood or particle board
  • Cut boards to size using a circular saw
  • Double check that all pieces fit correctly before proceeding

Cutting accurate base pieces is crucial for getting a precise fit with the quartz slabs.

Securing the Base

With the right size base boards cut, secure them properly to the cabinets.

  • Run a bead of construction adhesive along the top of the cabinets
  • Set base pieces in place, pressing down firmly into the adhesive
  • Attach boards with screws, drilling pilot holes to prevent splitting
  • Use shims if needed to fill any gaps between the base and cabinets
  • Allow adhesive to fully cure before installing quartz (usually 24 hours)

Properly securing the base prevents movement and provides increased stability for the heavy quartz.

Apply Sealant

The final step is sealing the base to prevent moisture issues.

  • Run a thin bead of caulk/silicone along the seam where the base meets the wall
  • Also apply around any cutouts for sinks or appliances
  • Smoothen the caulk with a wet finger before it dries
  • Allow caulk to fully cure before installing quartz

Sealing with caulk or silicone creates a moisture barrier between the quartz and base.

Preparing for Quartz Installation

Once your base is secured and sealed, you’re ready for quartz fabrication and installation. With a flat, even, and properly supported base, your quartz countertops will install smoothly and perform beautifully. Investing the time in an appropriate base provides the foundation for many years of enjoyment from your new quartz counters.

Frequently Asked Questions

What thickness plywood should I use for the base?

3/4″ thick plywood or particle board is ideal for providing a sturdy base for quartz countertops.

Should I use construction adhesive and screws?

Yes, using both adhesive and screws provides the strongest attachment to securely anchor the base.

What kind of caulk is best?

100% silicone caulk is recommended for its durability and water resistance along the seams.

How long does construction adhesive take to cure?

Adhesive usually takes a full 24 hours to fully cure and form a strong bond.

Can I install my quartz right after securing the base?

It’s best to wait until the adhesive has cured, usually 24 hours. This prevents any shifting.

How can I ensure my base is level?

Check cabinets for level and use shims during base installation. Also run a long level across tops of base boards.


Applying a proper base is an important process when installing quartz counters. With attention to a level cabinet foundation, accurate base sizing, secure attachment, and sealing, you can create the ideal surface for flawless quartz installation. Taking the time to correctly apply the base means your beautiful new quartz countertops will provide lasting function and style.