Granite

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Summary

Introduction

Granite has been used as a building material since ancient times. It is one of the oldest and most durable building products available, and will far outlast the building in which it's installed. It has become the material of choice for today's luxury homes and offices because of its enduring beauty, and because no synthetic material can yet compare to its elegance and performance.

Products made of this stone will not depreciate whit time and will continuously add value to any property where they are installed. Unlike synthetics, granite presents a surface depth that seems almost three-dimensional. It has a luminance that's absent from other surfaces. Regardless of its finish, granite creates an immediate impression of elegance, and is considered a definite plus on any real estate broker's checklist.

Granite is frequently used not only for kitchen countertops, bar tops, and vanities, but also for walls, floors, fireplace surrounds, windowsills, and even building fascia. Its unique variations in color and veining turns make each specimen a natural work of art. It is cool to the touch, and presents an image of classic grace and beauty.

Granite, being an igneous rock (formed from volcanic activity), differs from marble, limestone, and travertine in that those are sedimentary stones composed mostly of calcite, a relatively soft and common mineral derived from animal skeletons and shells. Millions of years of compression and heat below the earth's surface turned them into stone.

Granite is one of the hardest stone available, having a rating of 6 on the Moh's Measurement of Hardness Scale. In contrast, marble is rated only a 3. And since their main component is calcium, marble and the others are more susceptible to damage by acids such as vinegar and citrus beverages.

Several factors affect the price of granite, but the most important are supply and demand. Supply is the affected by the accessibility of the quarry, the uniformity of the stone within the quarry, and the stone's workability. A granite that is exquisitely figured, one that contains rare colors (e.g. blue), or one that is found only in a third world country will be more costly.

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Origins and Sources

Granite is believed to have been formed as long ago as 300 million years. It began as a mass of molten rock, estimated at 1300-1400 degrees F., formed by volcanic activity about 11-12 miles underground. Forces of nature caused the magma to gradually rise to the surface where it began to cool slowly over the next million years or so, solidifying into granite.

Over the time, the land above it eroded, leaving a scattering of granite quarries all over the world. Aside from the traditional sources, such as Italy, USA and Canada, popular granite producing areas now include India, China, many African nations, much of mountainous South America, and the northern European countries.

Granite is composed primarily of feldspar, quartz, and mica. It may also contain hints of muscovite, biotite, hornblende, and pyroxene and other minerals. These minerals are what give it its various colors. The white mineral grains in granite are feldspar, our planet's most abundant rock, which makes up about 60% of the earth's surface. The light gray, glass-like veins are quartz, and the black, flake-like veins are biotite or black mica.

Other minerals imbue the stone with a rainbow of color, depending on their source, and these varieties are often given unique names. One coarse grained type, for example, is called pegmatite, which is often rich in rare elements such as uranium, tugsten, and tantalum.

Granite is drilled and blasted from the quarry in large blocks, cut into slabs by a gang saw, and polished to uniform thickness by automatic polishing machines. The size of the slabs will vary from quarry to quarry, but are rarely more than 10 ft. long. It is cut and fabricated into countertops using saw blades.

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Physical Characteristics

Granite is crystalline in structure, so it always has tiny pits or spaces between the various mineral crystals. They are not visible prior to polishing, and usually remain unobtrusive on finished pieces once the surface is highly polished. Granite also contains natural fissures that may appear to be cracks, but they are not structural defects and will not impair the function or durability of the material. They occur naturally and are considered to be part of beauty of stone.

Warning !!! Granite is not recommended to customers who prefer surfaces that are perfectly uniform in color and pattern , those that are totally free of blemishes. For those individuals, engineered stone would be the preferred choice.

Due to quarry variances, granite slabs are sold in random sizes. A typical slab will measure 4-5 1/2 ft. wide and 7-9 ft. long. This is most important in dealing with islands, since most people want an island with no seams. Therefore, it's important to know in what size a preferred slab is available before making a selection. The only way to know is to call the fabricator each time an order is placed because slab sizes can change.

Granite is very heavy. Most varieties are available in both 2 cm (3/4") and 3 cm (1-1/4") thicknesses with a tolerance of +/- 3 mm. Our more popular thickness, and approximately 18-19 lbs. per sq. ft. in 3 cm (1.18") thicknness. Therefore, an 8 ft. top 3 cm thick will weigh between 144 and 152 lbs.

Ideas !!! Granite is not always a uniform thickness. Customers should be aware that their slab may vary in thickness as much as a quarter inch over the length of the slab. The installer must compensate for these variations with additional support, as needed, at the time the granite is installed.

Although granite is very durable when it's installed properly, it's not unbreakable. It can be chipped or cracked if it's struck a sharp blow by a heavy object. It can also break if it's dropped during installation. It is not flexible , and will crack if it is forced to twist or bend. Therefore, granite should only be handled by professionals and must always be adequately supported by proper framing or cabinetry.

Granite is the least susceptible of all natural products to scratches. If not abused, it will hold its luster forever. However, harsh chemicals and abrasive cleaners will dull the surface over time.

Granite will not scorch or burn through ordinary use. It's also resistant to stains. However, a few varieties may absorb some moisture with prolonged contact. Usually, no evidence remains when the liquid is removed and granite dries, but this could be a problem with dark pigmented liquids or oils. A stone sealer should always be applied to its surface after installation.

The quality of granite is highly subjective. The "best" granite is the one that best suits the need of the buyer, both for aesthetic and practical reasons. However, it is often rated on its luster when polished, its surface porosity, and its mingling of colors. Nearly all examples are quite suitable for counters, floors, and walls. There are lower grades available, but few are sold by reputable suppliers. The quality of the finished product lies more in the workmanship of the fabricator than in the product itself.

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Color and Pattern

Granite is primordial stone with naturally occurring variations in color, tone, granularity, pattern, etc. These variations, referred to as "movement" should be expected and are the source of its natural beauty.

Also, keep in mind that the veining in the granite can effect color perception. Sometimes two different grain sizes occurring in the same slab will appear to be different color. Mineral concentrations may cause patches that appear darker or lighter.

Consumers who are less acquainted with the material may expect the granite ordered to be identical to the sample they were shown. While the samples are intended to represent the quarry's product, each slab may differ slightly in color and veining. Indeed, even a single granite slab will have color variations from one end to the other. This lack of predictability gives the product its unique character and adds element of the nature into human-designed spaces. Indeed, each specimen is an original artwork.

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Fabrication and Finish

Fabrication costs can significantly affect the final price. Generally, the more complex the shape of the project and particularly the shape of the finished edges, the higher the price will be. Fortunately, a single thickness plain polished edge makes an excellent appearance and most customers choose this standard, especially when using 3 cm (1 1/4") thickness.

Occasionally, a customer will want a custom edge pattern, possibly to match the edge to detailing on the cabinetry, and this can also be done. But keep in mind that if the fabricator has to buy a custom cutting bit, he will add the cost to the price.

Fabricators may sell finished pieces, but slabs are always sold intact. The price includes the cost of transportation, making field measurements and templates, cutting, polishing, delivery, and installation. The total material required is determined by the layout and the amount of waste. The fabricator will try to lay out each job so as to minimize waste yet maximize the natural beauty of the veining and pattern.

Granite is usually polished to a high gloss finish. It is also available in a "honed" finish if desired, but this will increase the cost. Granite can be finished a number of styles:

  • Acid Etched finish (marble only) - rusticated through the application of abrasive or acidic agents.
  • Brushed finish- brushed with a coarse rotary-type wire brush.
  • Flamed/thermal finish - roughed by intense hear flaming to expose grains of stone.
  • Honed finish - satin surface with little of no gloss.
  • Polished finish - glossy, bringing out the full color and character of the stone.
  • Sandblasted finish - matte textured with no gloss. Recommended for exterior use.

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Sinks and Cook Tops

Usually, a sink will be mounted somewhere in the top. Sinks may be the self-rimming type that are mounted on top of the countertop, or under mount sinks that are installed by clips attached to the underside of the countertop and having a finished bowl opening. Sinks may be stainless steel, cast iron, and synthetic stone, or a number of other materials.

When choosing a sink, it is vitally important to make certain that the sink will fit in the cabinet in which it is to be mounted. Keep in mind that the cabinet must always be wider than the sink, I.e. a 30" sink will not fit in a 30" cabinet. There must also be ample room available for the faucet of your choice and any other accessories you may select.

Due to their weight, an under-mount cast iron sink cannot be anchored solely to the granite top, but must have a support frame built into the cabinet by a carpenter.

If a cook top is to be mounted in the granite, be sure that there is room inside the cabinet to hold the top and pop-up vents that will be installed with it.

All of these items must be on the job site before templates can be made.

Note: In the case of both sinks and cook tops, allowances must be made for the thickness of a backsplash when measuring for the placement of these fixtures. If thicker granite is used, a wider space will be needed.

If the top is replacing an existing top, be aware of the differences in thickness of the two materials. Any upper cabinetry that currently rests in the existing top will probably not reach the granite, so adjustments will have to be made.

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Installation Considerations

All ordinary cabinets with frames that are securely fastened to the wall easily support granite countertops. The weight of an average person standing on the cabinet puts more strain on the cabinets than a granite countertop.

Counter tops are measured in much the same way as other solid surfaces. First, a template must be made to use a pattern. For this reason, base cabinets must be permanently anchored in place before measurements can begin. They are to be installed only by the fabricator who will assume responsibility for a proper fit. Improper installation of kitchen countertops may void the manufacturer's warranties and result in damage to you fine surface or other areas of your kitchen, such as cabinets, drawers , sinks, and fixtures.

Be sure to allow sufficient lead time for the project to be completed. It will take 2 to 3 weeks to complete the installations after measurements are taken. In the event something goes wrong during the fabrication process, or if the top is damaged and has to be replaced, that time will be extended.

Because granite is usually sold in slabs no more than 10 feet long, most countertops will require one seam. And since granite is sold in rectangular pieces, using seams may also reduce the cost, as in an "L" shaped corner.

Seams will always visible in granite. Their visibility is affected by the granularity, color and pattern of the stone. Seams on a small, uniform grain or dark color will not be as noticeable as they will on a larger variegated grain or lighter color. A dramatic pattern with swaths of color will similarly highlight seams more than a uniform pattern:

  • Seams are always made on a straight edge. Although granite is very heavy, there could be some movement along the seam. To seal them, industry standards call for a special stone resin between 1/16" and 1/8" wide.
  • Individual slabs can vary slightly in their thickness. If not corrected, this would result in an uneven seam, so the installer will install shims on the underside of the top to bring the upper surface flush. This is considered to be the proper technique for leveling the surface. Granite may or may not be installed over plywood; the fabricator will decide that.
  • In most cases, some type of back splash is used. It can be thee same granite used for the counters, ceramic tile, or some other product. It may be attached to the counter or to the wall, but in either case the seam between the counter and the backsplash will be sealed with caulk. The standard height for a backsplash is 4" although they're frequently made higher if the customer desires.

Remember that the thickness of the backsplash must be considered when taking surface measurements.

  • Most counters are installed with a standard over hang of 3/4". This may be modified to suit personal taste, but it must be stipulated before the template is made.
  • Granite can be cantilevered up to 14" if it's a large piece with sufficient support in the fixed end. It should never be cantilevered where it might receive excessive stress, however, such as where someone may be tempted to sit on it or use it as a step stool to change a light bulb. In these cases, it must always be supported.

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Preparing the Site

On new construction, the base cabinets must be permanently anchored in the place before a template can be made. On a remodel project, existing tops must be removed prior to measurements. Any sinks, faucets, cook tops, or any other item that requires a cutout or a hole in the top must be on site and readily available at the time the template is made. The fabricator may need to take some items with him to complete the fabrication.

Please note that any delay in acquiring the accessories may also delay the installation.

Once the installer takes his measurements and makes the template, no changes can be made. All cuts are final; it is impossible to re-attach a piece of granite that has been cut from the slab. Additionally, once the granite is glued in place on the cabinets, moving it is very difficult and risks damaging the cabinets.

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Living with Granite

Unlike marble, synthetic and laminate countertops, granite countertops will not blister, scratch or chip under normal use. It is heat resistant, so a hot pot can be placed on it without using a trivet or pad. Its polished surface is ideal for rolling out pastry dough. Granite countertops are a beautiful, durable and cost competitive solution for countertops.

However, granite is subject to staining and etching if not maintained with sealers.

Granite is porous and it will absorb oils, such as cooking oil and grease, leaving a permanent dark spot unless sealed. Hairspray leaves a residue, and many common foods and toiletries contain acids and other ingredients that may etch or dull the stone surface.

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Protecting the Surface

Granite is a natural stone product and has a certain porosity. Therefore, after installation, it must be cleaned and sealed. ONLY impregnating sealers that are semi-permeable are accepted. Impregnators do not cover up the natural beauty of the stone and do not wear off like surface coating. We recommend using products from Stone Tech Professional for cleaning, sealing and maintaining natural stone countertops & grout. (Purchase Products)

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Keeping it Clean

Clean up generally needs only warm water and mild liquid detergent.

Most general purpose cleaners will etch or damage the stone or degrade the sealer, therefore removing protective properties and becoming susceptible to stains.

Maintenance cleaning with a ph-balanced, neutral cleaner will help remove soils that normal dusting or damp mopping leave behind. It also helps your stone free of dust and dry, sandy soil to minimize wear patterns from everyday use on some softer stones.

Specially designed cleaners for stone will also never break down the protective sealer. In fact, some cleaners contain protective properties which reinforce the sealer and prolong stain resistance.

For heavier cleaning jobs, using formulated for stone cleaners will effectively remove tough grime and messes yet be gentle on the surface.

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