How to Cut a Granite Countertop

Looking to cut new granite countertops for your kitchen? The tools required aren’t terribly uncommon or much different from tools for cutting sheet goods like MDF, for, say, bookshelves or a closet makeover. In terms of skills, if you can cut a sheet of plywood straight, there’s no reason you can’t learn how to cut granite equally as straight.

What to Know Before You Start Cutting Granite Countertops

Caveat #1: Use a Professional

This is a significant caveat. While the actual cutting of granite may be DIY-able, layout and templating kitchen countertops is generally not the domain of the DIYer. In fact, for pros, it is generally reserved for a specialist. Even the most carefully framed kitchen wall against which the counter will go has undulations and nuance, and invariably an inside corner that isn’t 90 degrees, especially in an old house.

Most kitchen installation professionals sub this work out to specialists. There are many reasons; just to name a few:

• Weight: In even modest kitchens or kitchens with just an “L,” granite countertops are far too heavy for most remodeling crews to handle effectively.
• Risk: Granite is great as a countertop, paving stone, or Belgian block—the latter two being very DIY-able—but, added to its weight is its expense and brittleness. A broken countertop not only costs money; it costs weeks to reorder. Again, most pros reserve this for a specialist.
• Skillset: While most remodelers have the skills and tools to cut granite, the process requires its own setup, dust or water control measures, and assurances for accuracy. Put another way, cutting and handling granite is an “all or nothing” affair. Get the sink cutout wrong by ½ inch and the sink is either off-center or it hits the base cabinet when you try and drop it in the hole—or both!

Caveat #2: Some Kitchens Might be DIY-able

However, not every kitchen is a maze of 6-foot-wide islands or inside and outside corners.

A galley kitchen with a short, straight run may be worth considering DIY-ing. Maybe if you can get an off-cut or sale-price slab, it’s worth a shot. But, still, it’s granite. The cheap stuff isn’t cheap.

A kitchen countertop with a straight run or a bar top, decorative shelf, or breakfast counter can be made from stone, and it will help to know how to cut a granite slab to do or oversee these kinds of projects.

Do Your Prepwork

• Granite can be cut wet or dry. In either case, it’s a mess, so set up a work area, with tables that can support the granite, where the work won’t affect other areas of the home.
• Cutting wet (which will probably require buying or renting a wet-cutting saw) will create a slurry that needs to be hosed off. Cutting dry creates a dust cloud that will travel.
• Ear, eye, and dust protection are essential.
• The primary cutting tools for granite are a circular saw or an angle grinder.

How to Cut a Granite Countertop

1. Set up granite on a stable work surface and clamp it down.
2. Measure and mark the cut line. To minimize chip-out, cover the cut line with blue tape. Remeasure and mark the tape.
3. If using a circular saw, blue-tape the shoe of the saw to minimize the risk of metal-on-granite scratching.
4. If using a grinder DO NOT remove the guard. A face shield is recommended.
5. Set up a straightedge guide like a shoot board.
6. Using an angle grinder is a freehand-cut method.
7. Whichever tool you use, keep the tool moving, but do not force the tool. This will minimize chip-out and deliver the cleanest cut. If the tool is really laboring, make the cut in two passes.
8. Some installers back-cut the slab. In other words, they make a 2-inch kerf at the finished end of the cut, so the granite doesn’t significantly chip or break upon completion of the cut.
9. Use an angle grinder with polishing pads to clean up the saw marks on the cut edge and to “break” or micro-bevel the 90-degree cut edge to soften it. Pads start at 50-grit and go up to 3000 or more depending on the smoothness and sheen desired.
10. The process is mainly the same to cut granite countertop for a sink. To transition directions, holes are drilled in each corner of the granite slab at the sink location and plunge cuts are necessary to enter the granite surface.