Quartz countertops are a popular choice for many homeowners due to their durability, aesthetic appeal, and ease of maintenance. However, one question that often comes up is whether you can cut or alter quartz counters after they have already been installed. The short answer is yes, quartz counters can be cut, but there are some important factors to consider.

Understanding Quartz Countertops

Before delving into the specifics of cutting quartz after installation, it helps to understand what quartz countertops are and what makes them different than other countertop materials.

Quartz counters are engineered stone slabs made from roughly 90% ground natural quartz crystals combined with polymer resins and pigments. The exact ratio and compounds can vary between quartz brands and colors.

Unlike natural stone slabs, the resins make quartz more flexible and non-porous. The material is also harder than granite and less prone to stains, scratches, and heat damage. Pre-fabricated quartz slabs are cut to size for installation in homes and businesses.

The non-porous nature and density of quartz is what makes it possible to cut after installation, but also contributes to the challenges, as discussed next.

Cutting Quartz Counters Post-Install

Quartz countertops can indeed be cut after they’ve been installed in your home. However, it is not as simple as just taking a saw to the material. Cutting requires special tools and techniques.

Challenges of Cutting Installed Quartz

There are a few factors that make cutting quartz counters after installation more difficult:

Density – Since quartz is engineered and non-porous, it is denser and harder than natural stone. This makes it more resistant to cutting.
Support – Having the full weight of the slab supported makes cutting easier. Once installed, providing adequate support can be tricky.
Access – Making straight cuts or holes requires room for cutting tools. Installed counters with backsplashes and walls make access more constrained.
Vibration – Cutting generates vibration which can damage adjacent surfaces when installed.
Mess – Cutting an installed counter creates quartz dust and debris on site.

While these challenges make post-install cuts more trouble, none make it impossible. It just requires the right techniques and tools.

Proper Cutting Techniques

Cutting quartz already set in place takes precision. Follow these tips for best results:

Use a respirator – Quartz dust is hazardous to breathe. Wear a respirator mask to avoid inhaling particles.
Support the slab – Prevent cracking by supporting the weight of the slab near the cut line.
Make gradual cuts – Don’t cut all the way through in one pass. Do multiple light passes to reduce vibration.
Use a diamond blade – Carbide blades designed for stone cutting are required to cut quartz. Diamond-tipped blades work best.
Go slow – Cutting too fast can crack or chip the slab. Go slowly and gently.
Minimize vibration – Allow the tool to do the work. Don’t force the blade as it can transmit vibration.
Cut underside first – For holes or sink cut-outs, shallowly cut the underside before going through from the top.

Proper cutting technique minimizes the risk of damage and creates clean edges. Patience is critical.

Recommended Cutting Tools

For best results cutting installed quartz, use specialized stone cutting power tools:

Stone router – For cut-outs, a rotary stone router with diamond burr bits does precise work. Go slowly.
Angle grinder – Fitted with a diamond blade, a 4-1/2″ angle grinder can cut straight sections. Minimize vibration.
Jigsaw – For freehand cuts, a jigsaw with a tungsten grit or diamond blade allows control. Cut shallow initially.
Hole saw – Diamond hole saws can create clean openings for fixtures. Backing the hole prevents chips.

While a circular saw or masonry blade can technically cut quartz, the results are imprecise. Investing in the proper quartz-specific tools prevents errors and damage.

Hiring a Professional

Cutting installed quartz counters is challenging. For complex cuts or large jobs, consider hiring a professional fabricator. They have the right tools, experience, and techniques to handle the job safely.

The pros can also seamlessly patch seams or install new edges after cutting accurately. This avoids ragged edges or sloppy glue work.

Examples of Post-Install Quartz Cuts

Quartz countertops can be cut in various ways after initial installation. Here are some common examples:

Cutting Out Sections for Sinks or Appliances

One of the most frequent needs for post-install cutting is to open up sections for undermount sinks or appliances. Using a router, hole saw, or angle grinder, neat openings can be made. Just be sure to make gradual cuts and support the slab weight.

Shortening Counters or Removing Sections

If measurements were off or designs change, quartz slabs can be shortened by cutting lengthwise. A diamond blade in an angle grinder can make straight cuts. An edge will need capping.

Removing a section entirely just requires cutting it free on all sides. This is useful for accommodating dishwasher openings or appliance corners after the fact.

Cutting Openings for Fixtures or Plumbing

For electrical outlets, soap dispensers, taps, or any fixtures being added after install, hole saws make clean circular cuts. Diamond grit blades give the smoothest edges.

Adding Edge Profiles or Changing Edges

The original edges can be cut off and new edges created to change the look or fix damaged edges. A professional can cut, fabricate, and seamlessly install new edges.

Creating Cut-Outs for Inlays

For a decorative inlay or artistic look, segments can be precisely routed out to inlay other materials. This requires careful measurement and execution.

Pros and Cons of Cutting Quartz After Installation

There are both advantages and disadvantages to cutting quartz counters after they have already been installed:

Pros

Allows modifications after installation if needed
Can accommodate undermount sinks or appliances not pre-cut
Provides flexibility if measurements change or issues arise
Less material waste if custom cutting on site
Ability to create openings or designs per homeowner preferences

Cons

More difficult and higher chance of cracking or chipping
Requires specialty diamond tools and experience
Limited access once secured to cabinets or walls
Requires professional help for complex or large jobs
Dust and debris created on site that requires cleanup

For straightforward jobs or smaller openings, post-install cutting can make sense. But for major changes or complex work, removing and fabricating new slabs from scratch may be better.

Factors That Can Affect Cutting After Installation

Not all quartz countertop installations are equally suited for after-install cuts. Several factors can limit cutability or precision:

Slab thickness – Thinner slabs are more prone to cracks from vibrations.
Overhang length – Long overhangs without much support are riskier to cut.
Fit to walls – Tight clearances make access more difficult.
Countertop support – Cantilevered sections or weak support can shift from tool vibrations.
Backsplashes – Tile backsplashes prevent cutting access from the rear.
Number of cutouts – The more holes that need drilling, the higher the chance of errors or marring.
Desired precision – Intricate inlays or artistic cuts are less feasible than basic openings.

Evaluating these factors before cutting will set proper expectations. Some jobs simply aren’t possible or practical after installation.

Cutting Precautions for Installed Quartz Counters

To ensure safe and satisfactory results when cutting quartz after installation, keep these precautions in mind:

Turn off electricity and gas to avoid sparks or shock risk.
Cover nearby surfaces to minimize dust contamination.
Wear eye protection, respirator mask, ear plugs, and gloves for safety.
Clear the area of objects that could vibrate loose and fall.
Avoid leaning on the counter while cutting to prevent shifting or cracking.
Make gradual, shallow passes when cutting rather than forcing it.
Keep spraying water on the blade during cutting to minimize heat buildup.
Check that your saw blade is sharp, clean, and the right size.
Allow time for precise work rather than rushing through it.
Start cuts from the backside/underside before finishing from the visible top side.

With care, safety, the proper tools, and some patience, cutting installed quartz yields professional looking results. Just don’t expect it to be as simple as cutting before installation.

Can You Cut Overhang on Installed Quartz Counters?

Overhangs on kitchen counters provide space for seating. But sometimes quartz overhangs end up longer than desired after installation. Fortunately, you can cut them shorter.

The key is providing ample support underneath the overhang while cutting it. Here are a few options:

Build temporary plywood support structure under the overhang area during cutting.
Have someone hold up the overhang portion from underneath while cutting above.
For thin overhangs, rent an adjustable countertop jack to support it. Position it just below the cut line.
Hire a professional installer to remove the countertop, cut it accurately with proper tools, and re-install it.

Attempt to make cuts gradually across the overhang width rather than all at once. Go slow and steady for clean results.

If overhang support structures like corbels have already been installed, you’ll need to detach them first before cutting, then re-install them on the shortened overhang.

Cutting Holes in Quartz Counters Without Chipping

Cutting holes for sinks and fixtures after installing quartz counters has a high risk of chipping, cracking, or flakes around the hole edge. Here are some tips to prevent that:

Mark the hole location and drill a small pilot hole from the bottom side first as a guide.
Use masking tape around the planned hole location to prevent surface chips.
Consider starting the hole from below the counter if accessible, only cutting through the bottom.
For round holes, use a hole saw specifically designed for stone/quartz cutting. Go slowly with a guide hole.
Back the hole by placing a piece of scrap wood at the hole exit point so the drill cuts into it.
For square or irregular holes, make a series of closely spaced hole saw cuts and then knock out the waste piece with a chisel and mallet.
Avoid hammer drilling unless as a last resort. The impact action tends to crack quartz around hole edges.
Clean hole edges with fine sandpaper to remove any small chips. Finish by buffing and polishing with quartz stone polish compound.

With care, patience, proper tools, and techniques like backing holes and starting cuts from below, chips can be minimized when cutting openings.

Cutting L-Shaped Sections in Quartz After Installation

Creating L-shaped cutouts in a quartz countertop that’s already installed takes advanced skill. But it can be done using the following careful process:

Outline the inside dimensions of the L-shape on the quartz using masking tape.
Set up a straightedge guide to run the angle grinder along when making long straight cuts.
Use a carbide grit hole saw to drill access holes inside the L-shape outline. This allows inserting the angle grinder.
Make incremental cuts through the slab where possible using the hole access points.
Cut most of the way through the short sides of the L-shape first.
Support the weight of the slab while working to prevent cracks.
Finish the long cuts to complete separating the L shape cleanly.
Carefully chisel away any remaining thin sections connecting the L shape cutout.
Smooth and polish all cut edges. Fill any small gaps with clear epoxy resin.

It takes great care to achieve clean 90-degree edges. Having a professional fabricator perform the work can ensure precision. But with preparation, the right tools, patience, and skill, DIY L-shaped cutouts are possible in installed quartz.

Can You Cut 3 cm Quartz Countertop After Installation?

Thinner 3 cm (1.25 inch) quartz countertops are more delicate and prone to cracking but can still be cut after installation in some cases. Here are tips for successful cuts:

Support the entire slab near the planned cutout area so the weight doesn’t cause cracking.
Use weaker pressure and slower feed rate when cutting to reduce vibration transmission into the thin material.
For sink or appliance cutouts, consider drilling access holes first, then making small incremental cuts rather than one pass.
Limit long straight section cuts as much as possible since this puts the most tension across a thin quartz slab.
Use sharp, fresh diamond cutting wheels and bits to reduce cutting force needed.
Cut from the bottom/backside first before finishing cuts from the visible top side.
Fill any hairline cracks that form with clear epoxy resin to prevent further spread.
Any overhangs should be well supported near the cut lines too.
For complex cuts, removing and fabricating the slab offsite by a pro may be the best method.

While requiring extra care, 3 cm quartz can be cut after installation for limited applications by taking it slowly and supporting the weight properly during cuts.

Can You Cut Installed Quartz Countertops with a Circular Saw?

It is possible but not ideal to cut installed quartz counters using a standard circular saw. Here is what to know:

The saw must have a diamond masonry blade. Carbide alone won’t cut quartz cleanly.
Running water over the cutting line is a must to cool the diamond blade. Friction builds up fast.
Clamp a straightedge securely as a guide to make straight cuts across a counter.
Cut very slowly and gently to minimize vibration transmission through the slab.
Supporting the slab weight near cuts helps prevent cracking from saw vibration.
Circular saws lack precision compared to router tools designed for countertop use.Edges can be ragged.
Chipping, flaking, and cracking are high-risk without optimal tools.
Large cutouts for sinks can’t be done safely with a circular saw.

For quick, simple shortening cuts, a circular saw is an option for installed quartz counters. But using the proper countertop fabrication power tools yields far superior results for most situations.

Cutting Quartz Countertops After Installation – The Bottom Line

While certainly possible, cutting quartz counters after installation introduces a number of challenges. The non-porous engineered stone is dense and hard on tools. The installed weight and lack of working space constraints access. And vibrating forces from cutting can potentially lead to cracking.

However, by fully supporting slabs during cutting, making gradual cuts with specialized diamond tools, and implementing other best practices, quartz can indeed be cut successfully after installation.

Small holes for fixtures or shortening overhangs tend to be easier than large cutouts or removing whole sections. Getting professional help is smart for major post-install modifications.

With reasonable expectations, the right techniques, patience, and care, installed quartz countertops can be cut and modified to accommodate changes – just don’t expect it to be as simple as cutting before installation.

Can a Quartz Countertop Be Cut After Installed? – FAQ

Below are some frequently asked questions about cutting quartz countertops after they’ve been installed:

Can you cut out a section of already installed quartz countertop?

Yes, it is possible to cut out sections of an already installed quartz countertop, such as openings for sinks or appliances. This requires using specialized diamond blades and carbide cutting tools. Make sure to support the countertop properly during cutting and go slowly to avoid cracking. Removing large sections is more challenging than making small cutouts. Hiring a professional fabricator is recommended.

How do you cut an oval in an installed quartz countertop?

Cutting an oval opening in installed quartz requires careful use of a rotary tool like a RotoZip with a diamond grit cutting bit. Start by drilling holes inside the oval area, then make incremental cuts between holes going slowly. Support the countertop near the cutout to prevent cracks. A temporary MDF template can also guide the rotary tool. Sand edges smooth after cutting the oval free.

Can you cut quartz countertop overhang after installation?

Yes, quartz countertop overhangs can be cut shorter after installation. Use supports or braces beneath the overhang during cutting to prevent cracking under its weight. Make incremental cuts across the overhang width rather than one end-to-end cut. Allow the diamond blade to gradually grind through rather than forcing the cut.

Should you cut quartz countertops before or after installation?

It is significantly easier to cut quartz countertops before installation. The slabs are fully supported on worktables, allowing straight cuts and openings using fabrication power tools. After installation, access is limited, vibration risks cracking, and clean results are harder to achieve. Only make minor post-install cuts when necessary.

Is it cheaper to cut quartz before or after installation?

Cutting quartz before installation is generally cheaper than after. Fabricators have the right workshop tools to make precise cuts efficiently. Post-install cuts require specialty diamond blades, go slower, risk damage, and sometimes require hiring pros. Getting the countertop pre-cut by measurements before installing avoids costly changes later.

Can any contractor cut quartz countertops after installation?

While any contractor can attempt to cut installed quartz countertops, results and risks