Uses & Maintenance of Granites
Countertops & Surfaces of Granites: uses & maintainance.
Uses: Kitchen/Laundry/Bath Countertops, Vanity Tops, Backsplashes, Wet Bars, Fireplace Surrounds, Wall Cladding, Tub Decks, Tub/Shower Surrounds,
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.
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 very slowly over the next million years or so, solidifying into granite.
Over 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.
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 the beauty of stone.
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 resistance to stains. However, a few varieties may absorb some moisture with prolonged contact. Usually, no evidence remains when the liquid is removed and the 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.
The Selection Process
Many customers are concerned about cost, but we sell several varieties of granite that are attractively priced. Once a customer sees that it will fit into the budget, the next step is to choose a color. But before this can be done, the buyer must decide whether the counter top will be the main focal point in the room, or another feature such as cabinetry.
Sometimes the customer may decide to mix and match counter top materials, with the outside counters being one material and the island being another. In some cases, an island may even be split into two levels, with granite installed on one side only.
Color and pattern
Granite is a 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 of a 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 an element of nature into human-designed spaces. Indeed, each specimen is an original artwork.
For these reasons, we always ask our clients to examine the actual slabs of material from which their tops will be cut.
The sample in our showroom may differ from the slabs currently available at the fabricator’s warehouse. They may have been mined from a different part of the quarry or they may have occlusions or color variances that give them a different appearance.
While color options are numerous, it’s usually best to choose a specimen that is stocked locally because of the cost difference.
If a slab has to be special-ordered, the freight would be prohibitive and the lead-time could be several weeks. In addition, the customer would have to agree to accept the color and markings sight unseen.
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 the 3 cm (1.18″) 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 custom cutting bits, he will add their 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 final 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:
- Abrasive finish – flat non-reflective surface, usually recommended for exteriors
- Acid Etched finish -rusticated through the application of abrasive or acidic agents
- Brushed finish – brushed with a coarse rotary-type wire brush
- Brush-hammered finish-varied texture, subtle to brushed by a mechanical process
- Flamed/thermal finish-roughed by intense heat flaming to expose grains of stone
- Honed finish – satin surface with little or 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
Granite tops can be finished with one of several standard edges.
Sinks and Cook tops
Usually, a sink will be mounted somewhere on the top. Sinks may be the self-rimming type that are mounted on top of the counter top, or under mount sinks that are installed by clips attached to the underside of the counter top 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-mounted 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 any pop-up vents that will be installed with it.
All of these items must be on the job site before a template can be made.
Note: In the case of both sinks and cook tops, allowances must be made for the thickness of a backslash 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 on the existing top will probably not reach the granite, so adjustments will have to be made.
All ordinary cabinets with frames that are securely fastened to the wall will easily support granite counter tops. The weight of an average person standing on the cabinet puts more strain on the cabinets than a granite counter top.
Counter tops are measured in much the same way as other solid surfaces. First, a template must be made to use as 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 counter tops may void the manufacturer’s warranties and result in damage to your 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 3 to 4 weeks to complete the installation after measurements are taken. If anything 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′ long, most counter tops will require at least one seam. And since granite is sold in rectangular pieces, using seams may also reduce the costs, as in an ‘L’ shaped corner. Sometimes a seam can be placed at a sink bowl to make it less conspicuous.
Seams will always be 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 small bead of silicone to be placed between the 2 surfaces to allow for natural expansion and contraction. This bead may be 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 surfaces 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 the 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 overhang of 1″.
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 on 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.
It’s always best to assume the worst and add proper support on any extension over 6″. An unsupported span of no more than 36″ is usually acceptable as long as the stone is supported on both sides of the span.
A special edge (e.g. ogee) creates an additional installation challenge where two sections of granite meet in a corner. Additional labor is required to match the two sections.
If a laminated edge is chosen using 2 cm granite, and if it’s to be mounted on frameless cabinets, or on framed cabinets that have upper retractable cutting boards, the granite will need to be raised ¾” to clear the laminated double edge that hangs down ¾”.
- Dishwashers should not be attached directly to the granite countertop, but be side-mounted to adjoining cabinets. Special brackets are available from the dishwasher manufacturer for this purpose. Drilling into the bottom of the stone can cause stress cracks and discolorations in the surface of the stone.
Preparing the site
On new construction, the base cabinets must be permanently anchored in place before a template can be made. On a remodel project, existing tops must be removed prior to measurement. Any sinks, faucets, cooktops, 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.
Under normal circumstances, the installer will not be responsible for connecting of dishwashers, cooktops, or plumbing.
Remember: do not make any changes to the design or specifications with the fabricator when he’s taking his measurements because those changes may affect other elements in the overall design or may result in unexpected cost increases. All changes should be arranged only through your kitchen designer.
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.
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 cool 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 it sealed. Hairspray leave a residue, and many common foods and toiletries contain acids and other ingredients that may etch or dull the stone surface.
A word about Black Granite
Most black granites are very dense and uniform in appearance and in general are the least porous with the least water absorption values. They should not be sealed as they are usually moisture resistant. Your fabricator will advise you.
It has been reported that some overseas factories are chemically treating Indian Absolute Black Granite to get a deeper, dark black coloration. However, in those cases where the granite has been chemically darkened, the stone is sensitive to food products, chemicals, ultra-violet rays and cleaning agents.
The granite takes on a lighter hue in the affected areas. The polish is unaffected, however, the stone turns light gray and it takes on cloudy appearance. While there are many very reliable sources for Absolute Black Granite, precautions should be taken to prevent installation of inferior/defective material. All Black Granite should be tested prior to installation.
Protecting the Surface
Granite is a natural stone product and has a certain degree of porosity. Therefore, after installation, it must be cleaned and sealed. Only impregnating sealers that are semi-permeable are acceptable. Impregnators do not cover up the natural beauty of the stone and do not wear off like a surface coating.