How to Level Existing Cabinets for Quartz Countertops

Installing new quartz countertops can transform the look of your kitchen or bathroom. However, quartz is very rigid and needs a perfectly flat surface for proper installation. If your existing cabinets and base aren’t level, you’ll need to take steps to flatten them out before installing the quartz. With some basic DIY skills and the right tools, leveling your cabinets for new quartz countertops doesn’t have to be difficult.

What You Need to Level Cabinets for Quartz

Leveling existing cabinets is an important preparatory step before installing new quartz countertops. Here’s a list of the basic tools and materials you’ll need:

  • Spirit level – An essential tool for checking level and identifying any high or low spots. Get a large spirit level that can span the length of your cabinets.
  • Shims – Small wood shims are used to fill any gaps under cabinets and raise them to be level. Buy a pack of assorted size wood shims.
  • Wood filler – Used to fill any large gaps for a smooth surface. Look for wood filler designed for interior use.
  • Sandpaper – For sanding down wood filler or high spots. Get a multipack of assorted grit sandpaper.
  • Screws – New screws may be needed to re-secure cabinets after shimming. Bring the old screws to match the size and type.
  • Drill – A power drill makes driving screws to secure cabinets much easier. A manual screwdriver can also work.
  • Tape measure – Important for checking measurements as you level and shim. Get a metal retractable tape measure.
  • Safety gear – Safety glasses, gloves, and a dust mask are recommended when sanding.

How to Level Kitchen Cabinets for Quartz Countertops

Here is a step-by-step guide for leveling existing cabinets in preparation for new quartz countertops:

1. Empty the Cabinets and Drawers

The first step is to completely clear out the cabinets and drawers. Remove everything from inside so you can access the base of the cabinets. This also prevents any items from falling out when leveling.

2. Check for Level

Use a long spirit level to check the cabinet bases for level, both side-to-side and front-to-back. Place the level along the cabinet bottom to identify any high or low spots. Mark any uneven areas with a pencil.

3. Loosen Cabinets from Wall

Before shimming, you need to loosen the cabinet base from the wall. Look for screws through the back panel into wall studs and loosen these. Don’t remove them fully.

4. Shim Under Low Spots

Use small wood shims to raise any low areas, sliding them under the cabinet base. Tap them gently with a hammer to adjust their height. Check with your level and add shims until flat.

5. Use Wood Filler for Larger Gaps

For any gap wider than 1/8 inch under the cabinet, use wood filler instead of shims. Fill the gap flush and allow to fully dry before sanding smooth.

6. Sand Down High Spots

Check for any high spots on the cabinet base using your level. Sand these down gently with sandpaper until even with surrounding areas.

7. Drill Pilot Holes for New Screws

Once fully level, drill new pilot holes through the back of the cabinet bases into the wall studs. Counterbore each hole so new screw heads are recessed.

8. Secure Cabinets to Wall

Drive new screws through the back panel of the cabinets and into the wall to firmly secure them in their new level position. Don’t overtighten.

9. Reinstall Doors and Drawers

With the bases now level, you can reinstall the cabinet doors, shelves, and drawers. Your cabinets are now ready for new quartz tops!

How to Level Bathroom Vanity Cabinets for Quartz

The process for leveling bathroom vanity cabinets is very similar:

  • Empty out the vanity and remove doors/drawers to access the base.
  • Check for level using a spirit level and identify high and low spots.
  • Loosen any screws securing the vanity to the wall without fully removing them.
  • Shim under low areas with wood shims until vanity base is level.
  • Apply wood filler to gaps wider than 1/8 inch before sanding smooth when dry.
  • Sand down any high spots on the vanity base until flat.
  • Drill pilot holes for new screws and secure leveled vanity back to the wall.
  • Reinstall doors, drawers, and plumbing fixtures.

Tips for Leveling Cabinets

Follow these tips for best results when leveling cabinets for new quartz countertops:

  • Take your time checking for level and shimming. Rushing can lead to uneven spots.
  • Use thinner shims for minor height adjustments and thicker shims for large gaps.
  • Stagger your shims, don’t stack them directly on top of each other.
  • Gently tap shims into place instead of hammering to avoid splitting wood.
  • Fill wide gaps with wood filler, not lots of shims, for easier sanding.
  • Be careful not to over-sand when smoothing high areas.
  • Secure cabinets back to the wall tightly, but don’t overtighten screws.

Common Questions about Leveling Cabinets for Quartz

How much gap is allowed under cabinets for quartz countertops?

For proper support, there should be no gaps larger than 1/8 inch under cabinets where quartz countertops will be installed.

Should I just replace old uneven cabinets instead of leveling them?

If cabinets are severely damaged or warped, replacement may be better than leveling. But leveling is ideal for cabinets in good condition, saving time and money.

What if my walls are uneven too?

In addition to leveling the cabinets themselves, any uneven spots on the walls should also be leveled using shims and fillers before installing the quartz.

Can I install quartz on cabinets that aren’t perfectly level?

It’s not recommended. Small gaps under quartz countertops can lead to cracks and other issues over time. Taking the time to properly level cabinets will provide the best long-term results.

How long does it take to level kitchen cabinets?

For an average sized kitchen with cabinets in decent shape, allow 2-3 hours to check for level, adjust with shims, and secure back to the wall. Leveling bathroom vanities takes 1-2 hours.


Installing new quartz countertops starts with proper cabinet prep. Taking the time to level any uneven base cabinets ensures your beautiful new quartz tops install cleanly and last for many years. With some basic tools and DIY skills, leveling existing cabinets can be a manageable process. Just be patient, check for level frequently, and use shims and fillers as needed for best results.