Quartz countertops are a popular choice for modern kitchens and bathrooms due to their durability, low maintenance, and stylish appearance. However, sometimes it becomes necessary to cut or modify an existing quartz countertop to accommodate changes in the space. Cutting a quartz countertop is not quite as simple as cutting a natural stone or tile countertop, but it can be done with the right tools, preparation, and techniques.
Things You’ll Need
- Tape measure
- Straightedge or T-square
- Painter’s tape
- Circular saw with diamond blade
- Jigsaw with tungsten carbide blade
- Angle grinder with diamond blade (for notches/cutouts)
- Ear and eye protection
- Rubber gloves
- Dust mask
- Shop vacuum
Planning Your Cuts
Before making any cuts, thoroughly measure and plan out the area you need to modify. Mark your cut lines with a pencil and use a straightedge as a guide. Apply painter’s tape along the cut lines to prevent chipping. Things to keep in mind:
- Allow an extra 1/8″ clearance on all cut lines for the blade kerf and smoother seams
- Avoid joining new seams directly over seams in the substructure
- For removing sections, drill access holes inside corners to allow space for the jigsaw blade
Always follow safety protocols – quartz produces fine silica dust when cut, so protect yourself and others in the workspace. Turn off any appliances/fixtures near the cutting area and cover adjacent surfaces to contain dust.
Cutting a Straight Section
Use a specialized diamond blade on your circular saw when cutting quartz. Wet cutting is recommended to minimize dust – keep a spray bottle of water handy to regularly mist the blade and cut line.
Here are the step-by-step instructions for cutting a straight section:
- Mark your cut line and apply painter’s tape to protect the surface.
- Set cutting depth on the circular saw to just above the thickness of the countertop.
- Position straightedge along the cut line to guide the saw. Clamp if needed.
- Mist the cut line with water to keep the blade lubricated.
- Make sure cord is out of the way, then start saw and slowly feed the blade through the cut line, keeping blade tight to straightedge guide. Let the blade do the work.
- Support the offcut section as you complete the cut to prevent damage.
- Make several finishing passes with increasingly lighter pressure to achieve a smooth edge.
- Vacuum cutting area thoroughly to remove all dust before removing tape.
Cutting Out Sections for Sink or Cooktop
Use a jigsaw with a tungsten carbide blade when removing a section of quartz for a sink or cooktop cutout. Follow these safe practices:
- Drill a 1″ access hole inside each corner to allow space for the jigsaw blade to turn.
- Set cutting depth just shy of countertop thickness to avoid hitting substructure.
- Cut slowly along marked lines – forcing the saw leads to chipping.
- Support the cutout piece from below as you cut to prevent cracking.
- Make finishing passes along cut edge with firm pressure for a clean cut.
- Round inside corners of cutout slightly for smooth fit of new sink/cooktop.
Smoothing Cut Edges
For polished seamless appearance, cut edges must be smoothed and polished after cutting. This can be done a few ways:
Use 100-150 grit sandpaper wrapped around a block to smooth cut edges flush. Sand evenly along the cut, checking frequently for flatness. Finish by wiping clean.
Diamond Polishing Pads
Special diamond polishing pads can refine the cut edge to a like-new sheen. Work through grits from 50 to 3000 using a handheld polishing pad starting on the roughest grit. Rinse pad frequently and wipe edge clean between pads.
Fit an angle grinder with a 100-150 diamond blade and carefully buff the cut edge smooth by working evenly along the length. Rinse and clean edge when complete. Be cautious to avoid overheating.
Cutting Notches or Holes
For notches needed to accommodate pipes or cables, use an angle grinder and diamond blade. Mark the outline of the notch and make relief cuts on the inside corners before cutting out the section.
For small holes needed for fixtures like soap dispensers, use a diamond hole saw attached to a drill. Cool the blade with water and drill slowly to avoid cracking.
Preventing Cracks and Chips
Cutting quartz does introduce some risk of cracking near the cut line. Here are some tips to minimize damage:
- Tape off the area surrounding the cut to prevent chips.
- Drill relief holes at inside corners prior to cutting.
- Support the cutout section from below as you cut.
- Use sharp diamond blades – dull teeth increase risk of fractures.
- Avoid twisting the saw blade during cuts.
- Cut slowly and gently without forcing the saw.
- Sand out small chips immediately to prevent cracks from spreading.
With the proper tools and techniques, existing quartz countertops can be modified and retrofitted to work for new layouts and fixtures. Just take time to measure carefully, follow safety precautions, and make cuts patiently for best results.
Can I cut quartz countertop with a circular saw?
Yes, a circular saw equipped with a diamond blade is an effective tool for straight-line rip cuts in a quartz countertop. Go slowly and use a straightedge as a guide for best control.
What blade do I need to cut quartz?
Specialized diamond-tipped blades are required to cut through quartz material. Use a diamond masonry blade on a circular saw for straight cuts, and a tungsten carbide jigsaw blade for curves and sink cutouts.
How do you cut quartz countertops without chipping?
- Tape off the area around your cut line with painter’s tape
- Mark your line and drill small relief holes at inside corners
- Cut slowly and gently with a diamond blade
- Support the cutout section from underneath as you cut
- Use a jigsaw for sink cutouts to give the blade room to turn
Can quartz countertops be cut to fit on site?
Yes, quartz countertops can be cut and modified on site to fit using the proper diamond-tipped blades and cutting techniques. Careful measurements, relief holes, straightedge guides, and slow steady cuts can achieve accurate modifications.
What should I seal my quartz countertop edges with after cutting?
After cutting and polishing the edges, seal them with a specialty quartz sealer/polish product applied with a soft cloth. This prevents moisture from getting into the porous cut edge and discoloring it over time.
How can I get a smooth finish on my cut quartz edge?
Use increasingly finer grit sandpaper or diamond polishing pads to smooth and refine the cut edge of the quartz. Start with 100-150 grit sandpaper, then switch to polishing pads from 50 grit up to 3000 for a glass-like polished edge.
Can I cut a new sink opening in my existing quartz myself?
Cutting a sink opening is an advanced job, but can be DIY’ed with the right tools and careful prep. Use a jigsaw and drill relief holes at inside corners. Cut just through the quartz, then sand and polish the edges for a pro-looking result.
What’s the easiest way to cut a notch in quartz for wires?
Use an angle grinder with a diamond blade for notching. First mark your outline, then make intersecting relief cuts on the inside corners. Remove the section by cutting between relief cuts. Smooth and seal the edges when done.
Is it okay to cut quartz countertop overhangs to square them off?
Yes, you can square off the overhang on an existing quartz countertop by cutting along the edge with a circular saw and diamond blade. Just be sure to measure carefully and cut slowly and smoothly to get a straight finished edge.
Cutting existing quartz countertops allows you to give them a second life and adapt them to new layouts and fixtures. With careful planning, the right specialty cutting tools, and good cutting technique, quartz can be modified on site with excellent results. Pay close attention to safety and proper handling of the quartz during cutting to prevent cracks and chips. Finishing the cut edges smoothly provides a seamless updated look. With some skill and patience, your modified quartz countertop can look like it was originally fabricated that way.