How Granite Countertops Work


Luxurious kitchen elements including a hammered copper sink basin and granite counter tops. See more pictures of home design.
­iStockphoto/Jim Kruger

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­Whoever coined the phrase "hard as a rock" might very well have been thinking of granite. Formed ov­er millions of years from compressed molten rock under the Earth's surface, granite is extremely hard and durable.

With its heat-resistant qualities, granite doesn't blister; it's also unlikely to scratch or chip. When used for kitchen countertops, it's far superior to marble, synthetic and laminate. It's also better-looking and has a luminous, dimensional quality when polished.

Granite is made up of interlocking mineral crystals, the most common being feldspar and quartz. But an array of other minerals can be included, and these make each piece of granite unique. Feldspar is the white mineral you see in granite; the light gray veins are quartz; and the black is typically mica [source: Keidel].

­Granite is drilled, chiseled and blasted out of quarries in large blocks, and special milling machines then cut it into workable slabs. Typically, a slab of granite is around 4 to 5 feet (1.2 to 1.5 meters) wide and between 7 to 9 feet (2.1 to 2.7 meters) long. Other machines polish the material into a uniform thickness, usually about three-quarters of an inch to 1 1/4 inches (2 to 3 centimeters) [source: Walton].

Turning raw granite into countertops requires special tools. Granite can be custom-made and professionally installed, but it's also available in precut and edged countertops. The kitchen's design, the shapes and sizes of the available precut material and the location of the seams will help determine if you can use precut and edged granite or if you need a custom installation.

Are you convinced that granite is the best choice for your kitchen or bathroom remodeling project? Read on to learn how to cut granite countertops.

Cutting Granite Countertops

Most granite cutting takes place at the quarry, but some will probably have to be done at the installation site. It's essential that the proper equipment is used.

To shape the dense material, a standard household skill saw needs to be upgraded with a diamond cutting blade. These are available at major home improvement centers for about $45. Pros also have a trick they use to avoid chipping the edge of the granite, which is caused by the blade's vibration. Collars that act as big washers on both sides of the saw's blade reduce the vibration, allowing a cleaner cut.

When granite is cut dry, a considerable amount of dust is generated. Some installers will use a handheld diamond-bladed radial saw with a vacuum attachment to help minimize the mess. A contour diamond blade is needed to cut out curves like sink openings [source: Walton].

The edge design of the countertop can be shaped in a number of ways: flat, beveled, curved or rounded. But it can be a challenge to cut the edges so they match perfectly or meet precisely in a corner -- unless you have access to an automated edge-shaping machine that both cuts and polishes the edge.

Assuming you don't want to buy an expensive piece of equipment, one option is to have a local company cut the edges for you. Typically they'll charge a fee per square foot that includes cutting, edging, profiling and polishing the countertops. Extra fees may apply to sink cutouts (getting these accurately sized for under counter-sink mounts is tricky). Don't forget the delivery charge -- granite is heavy and often requires two or more people to carry into your home [source: Larson].

Get out your big guns -- how to install granite countertops is next.

Installing Granite Countertops

Whether you plan to have your granite countertops fabricated and installed or want to do some or most of the work yourself, the process is labor-intensive and requires meticulous measuring and skill.

If you're installing granite in a kitchen, pull out the stove and refrigerator and remove the sink from the existing countertop. If the old top was screwed on, empty the lower cabinets and pull out all drawers and doors. Pry off your old countertop. Then tape cardboard or paper over all cabinet fronts for protection [source: Larson].

Accurate measurements are crucial. Be sure to note details like appliance openings. Usually, these are sized­ precisely, so finished edges will need to be flush with the cabinet ends. Templates are helpful in calculating cuts for sinks and cook tops. The thickness of the backsplash needs to be account­ed for as well, to ensure that elements like faucets will fit between the sink and the backsplash. You should use plastic sheeting or a vulcanized rubber paint-vapor barrier between the subcounter and the granite [source: Walton].

Most countertops will have at least one seam because the material typically comes in slabs that are less than 10 feet (3 meters) long. Whenever possible, seams should be made at well-supported areas of the cabinetry. Because there can be a slight difference in the thickness of two granite pieces, shims might be needed to ensure the tops are flush [source: Walton].

Silicone applied between the two slabs allows for expansion and contraction, and a special epoxy holds the granite in place. When the epoxy is joining two pieces of the countertop at a seam, it should be mixed with colored resin to blend in with the color of the granite. Use colored glue in any visible seams. You should also mix the resin with the caulking that secures the backsplash to the countertop [sources: Keidel, Marblemaster].

Fortunately, it's easier to maintain granite countertops than to install them. Learn everything about sealing granite countertops in the next section.

Sealing Granite Countertops

Although most granite countertops don't need to be sealed, it does help the stone resist dirt and spills, which can cause etching and staining [source: Marble Institute of America].

By its nature, granite is moisture-resistant -- however, it's also porous. Sealants block liquids from seeping into the granite. A properly sealed countertop will cause liquids to bead on the surface.

Liquids with color -- like grape juice and red wine -- cooking oil ­and fat can all discolor the countertop. Pizza grease can be a culprit, too, when it soaks through the bottom of the pizza box and onto the countertop.

In small areas where the faucets, sinks and stovetops lie, you should apply sealer after the countertop is installed. This should be done before appliances are put in because you won't be able to reach these spots later on -- but seeping liquids can [source: Hart].

Generally, you should seal most kitchen granite countertops annually. Keep in mind that different pieces of granite have different porosities. Some countertop areas may need to be sealed more often than others. To determine if it's time to reseal a countertop, dribble some water onto the countertop. If it beads up, great. If the water soaks into the granite, it's time to reseal.

Sealing is straightforward. Get a good-quality granite countertop cleaner, a granite sealer that's designed to resist water and oil-based stains, and some clean rags. Follow the cleaner's directions first, making sure the granite is dry before you start sealing. Some sealers, such as those with a solvent base, are good for several years [source: Marble Institute of America].

When sealing, work in small areas, allowing the sealer to absorb for the recommended amount of time before applying the second application. Then move to another area. Follow the sealer's recommended amount of drying time (usually several hours or overnight) before using the countertops.

Before making the decision about granite countertops, it's important to know the benefits and costs. Read on to learn about the pros and cons of granite countertops.

Granite Countertops: Pros and Cons

Like many things, granite countertops have their advantages and disadvantages.

Pros

  • Granite countertops don't d­epreciate in value.
  • It's a one-of-a-kind, natural surface that has an almost luminous look.
  • Granite adds value to your home.
  • It's sanitary -- bacterial contamination is not a problem with granite.
  • Formed by heat and pressure, it can take the heat of a pan.
  • It's easy to clean with warm water and a mild detergent.

Cons

  • Granite countertops last forever. If you get tired of the color, you'll either need to learn to live with it or rip out the entire counter, because you can't change the color.
  • Each slab of granite is different, so it may not be a good choice if you prefer a completely uniform look.
  • Granite itself is expensive, and the labor-intensive installation can run three times more than the cost of the material.
  • Granite can be permanently stained if you seal it with a preexisting stain.
  • It can crack when hit by a hard, sharp object like a meat cleaver.
  • Because it's so heavy, granite often requires additional structural support, especially in spans and cantilevers.
  • Once glued onto the cabinets, granite is quite difficult to remove, and may result in damage to the cabinets.

Now that you've read about how to install, cut and seal granite countertops, as well as granite's pros and cons, you might want a few more details before you begin your project. To learn more, visit some of the Web sites on the following page.

Related HowStuffWorks Articles

Sources

  • Carter, Tim. "Granite Countertop Stains." Ask the Builder. (Accessed 12/14/08) http://www.askthebuilder.com/N8_Granite_Countertop_Stains.shtml
  • Everlife Memorials. "Choosing a Headstone for a Family Member." (Accessed 12/16/08) http://www.everlifememorials.com/v/headstones/choosing-headstone.htm
  • Hart, Tim. "Granite is Hard, but Sealing it is Not." Washington Post, March 17, 2007. (Accessed 12/14/08)http://www.washingtonpost.com/wp-dyn/content/article/2007/03/16/AR2007031601672.html
  • Keidel Supply Company. "Granite Countertops and Surfaces." (Accessed 12/14/08) http://www.keidel.com/design/select/tops-matl-granite.htm
  • Larson, Travis. "Granite Tile Kitchen Countertops." Readers Digest, from The Family Handyman. October 2002. (Accessed 12/14/08)http://www.rd.com/17870/article17870.html
  • Marble Institute of America. "MIA Statement of Position on Sealing Natural Stone Countertops." Consumer Resources. (Accessed 12/14/08)http://www.marble-intitute.com/consumerresources/sealing_stone.cfm (Accessed 12/14/08)
  • Marblemaster. "Granite Countertops Frequently Asked Questions." Feb. 16, 2007. (Accessed 12/15/08)http://www.marblemaster.com/granite/granite_slab/faq.html
  • Walton, Larry. "Installing Granite Countertops." Extreme How To. (Accessed 12/14/08) http://www.extremehowto.com/xh/article.asp?article_id=60654