OVERVIEW Types of Natural Stone and Tile Quarrying Cuts and Matching Finishes Stone Construction Considerations When Specifying Maintaining Natural Stone Installation Examples
NATURAL STONE TYPES: TRAVERTINE Character: has voids, usually has some veining, variety of colors (mostly in the warm range). Formation: Travertine is a sedimentary rock formed by the precipitation of carbonate minerals. Applications: Floor and Wall Generally not chosen for kitchen countertops due to its low density, but travertine makes a beautiful countertop in a bathroom A popular choice for outdoor use; especially as cladding , pavers, or as pool surrounds. Travertine is naturally water „resistant” as it tends to push water out due to the way the stone is formed. Be sure to specify 1st choice travertine for most interior applications. This is the most dense material. Commercial grade travertine is much cheaper, but can be very sandy, disintegrate, and have large holes. Commercial grade may be appropriate for outdoor use in some cases—but not where erosion may be a concern.
NATURAL STONE TYPES: LIMESTONE Character: often has visible fossils embedded within, some color variety. Formation: Limestone is a sedimentary rock composed of different crystal forms of calcium carbonate. Most grains in limestone are skeletal fragments of marine organisms Application Floor and wall Not generally chosen for countertops due to its porosity and tendency to stain-- limestone is suitable for bathroom countertops, however. Not generally chosen for outdoor use for the same reasons, but it can be used with proper sealing Some limestones must be sealed from the front AND the back before installation to prevent the setting materials from staining the stone.
NATURAL STONE TYPES: MARBLE Character: Marble often has distinct veining with a wide variety of colors. Formation: Marble is a metamorphic crystalline rock formed when limestone has additional heat and pressure applied to it by the earth‟s crust, causing the stone to re-crystallize. Applications: Floor and Wall Countertops—occasionally. It is a popular material for bathroom countertops. It Can be too delicate for kitchen (depending on how the client will use it) New Sealing Products have made marble a more popular choice for interior countertops in recent years. Not usually a good choice for outdoor applications. Can be used in a sandblasted or other highly textured finish, but usually not preferred for countertops in outdoor kitchens or in wet areas.
NATURAL STONE TYPES: GRANITE Character: often has “busy” visual texture in a variety of colors. Formation: Granite is a plutonic igneous rock having visibly crystalline texture; generally composed of feldspar and mica and quartz Applications: Floor and wall: sometimes this is a desired look, but it can be very busy Countertops: the hardness of the stone makes granite the most popular choice for both kitchen and bathroom countertops. Suitable for any outdoor applications (be careful to choose the right finish) and exterior cladding
NATURAL STONE TYPES Slate Character: rough texture, mostly greys, but some varieties have dramatic some color variation. Formation: Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash Applications: Floor and wall: must consider shaling when choosing slate Not generally used as kitchen countertops due to shaling, but custom slab fabrication is available Great for outdoor use Quartzite Character: Looks similar to slate, but is harder and doesn‟t shale Formation: a very hard metamorphic rock consisting of a mosaic of intergrown quartz crystals Applications: Same as slate
NATURAL STONE TYPES Onyx Character: translucent, can range from gold and oranges to green. Formation: Onyx is a cryptocrystalline form of quartz. Onyx is a sedimentary rock, formed as stalactites and stalagmites in cave interiors. Applications Floor, Wall and decorative. Onyx can be delicate, so be careful where you use it. Most popular for Vanity countertops or specialty surfaces Soap Stone Character: Grey, sometimes greenish. With white veining. Smooth “soapy” feel Formation: a metamorphic rock that is largely composed of the mineral talc Applications: Generally used for countertops Chemical and heat resistant but NOT scratch resistant Can be delicate—must be oiled regularly to keep color
STONE PRODUCTION Sourcing Natural stone comes from quarries world- wide. Certain stones are available only in certain parts of the world. Italy, Spain, and Turkey are major exporters of different types of natural stone Quarries After a deposit of a desired stone is discovered, engineers design a quarry plan Stone is excavated using drilling and blasting techniques Long tunnels are drilled vertically Explosives are inserted and detonated Large boulders are removed and processed into useable tile and slabs at the factories Let‟s watch a quarry blast! Factories Large blocks from the blast are either cut into specialty items like sinks, bathtubs, etc, or cut into large slabs which are then planed and cut into tiles Factories have specially calibrated machinery to make 90 degree corners and straight cuts. Be sure when purchasing that tile is properly calibrated! How Granite is sourced and produced
CUT TYPES AND MATCHING Cross Cut: stone is cut parallel to natural Random Match: A casual, unmatched layers, creating a cloudy movement in the effect with no attempt at a pattern (most grain common application) Book Match: a mirrored-image pattern at the joint line that produces a nearly continuous Vein Cut: stone is cut perpendicular to grain. natural layers, creating a linear movement in the grain Variations of Book matching include: end matching, diamond matching, and quarter matching. These are all special order because the factory must recalibrate the machinery to produce this effect.
NATURAL STONE FINISHES Polished: A glossy surface finish that brings out the full color and character of the stone. The finest and smoothest finish available in stone, characterized by a high luster and strong reflection of light. Honed: This is a process to remove the saw marks/scratches left by the saw. This gives a softer, matte appearance to the stone. Honed and Filled: Before Travertine is honed, the natural holes are often filled with colored cement or resin to create a smooth surface Brushed: This process is done with a wire brush to make the stone have a soft or velvet feel to it. This process enhances and deepens the colors as well. Sometimes called “leather‟ finish. Tumbled: A special finish obtained by rotating pre-cut pieces of stone in a tumbler. This process produces a very rustic look with rough edges and rounded corners. Sand Blasted: This is accomplished by exposing the surface to a high pressure jet of sand that leaves the material slightly scratched on the surface. This finish is often used outside because it is non-skid. Flamed: A stone that has been thermally treated, creating a reddish-yellow color with uneven rough surface. Saw-Cut: This is the result when the stone is cut; the gang saw used leaves marks/scratches on the surface. Bush Hammered: A finish that creates a rugged surface full of little grazes that becomes non-slippery, also giving the stone a lighter shade. Split: Tile has a flat back with an uneven front surface, which offers a look like protruding bricks from the wall. Chiseled: A hand-made finish with deep textured line that could go in one or more directions. Can be rough or fine. Antiqued: Special machines that look like industrial washing machines are used to treat the pieces with abrasive elements (sand, shot blast) while a cylinder revolves. In a short time the impact on the stones with the abrasives produces an effect similar to aging caused by use and wear. Acid Washed: Stone is treated with a special acid to create a slightly textured finish—this is popular in shower areas, especially in stone shower trays. Can also be used to remove a polished finish from stone. Imitations of these finishes are often available in man-made and engineered surfaces, as
TYPES OF STONE CONSTRUCTION Rubble Stones are used as they are, or roughly shaped and laid with wide joints. Cobblestone Cobblestones are laid in horizontal rows with decorative mortar treatment to the horizontal and vertical joints. Ashlar Quarried stone is sawn to a particular size and the blocks fit closely together
TYPES OF STONE WALLS Structural - footing needed - coursed or non-coursed - filled with mortar - minimum 10” thick Decorative - footings still needed - coursed or uncoursed - fill with mortar - metal ties fasten decorative to structural wall
METAL TIE SYSTEM FOR DECORATIVE STONE WALLS Barnes Foundation on Ben Franklin Parkway
SPECIFICATION CONSIDERATIONS Residential Almost any finish is appropriate for any application—it‟s all about the preferred look Sometimes slipperiness is a client concern in wet areas when using polished stone—the abrasion coefficient between polished and matte is not so great that this is an issue on paper (many commercial applications use polished stone), but be sure to address any concerns with clients before specifying a material. Dust often makes stone more slippery than wetness—be sure to tell clients to dust mop their natural stone floors regularly Textured finishes (split) look great for walls, but be sure to explain to the client how to clean them (using a soft brush and stone cleaner). Consult your stone supplier for installation instructions in wet areas. Shower Floors: Must have small mosaics (most contractors prefer 2X2 or smaller, although 4X4 can work) UNLESS a linear drain is used Commercial There is far more regulation in commercial applications regarding slip resistance and abrasion. Be sure to know your city‟s or client‟s codes regarding these requirements. Thickness of Tiles Unlike porcelain tile, natural stone tiles vary in thickness from size to size (large format tiles must be thicker to prevent breakage.) Be sure when combining tile sizes to be aware of the difference in thickness as this will add to the labor. Sealer Natural stone should be sealed at the time of installation to prevent staining. Some people may prefer to re-seal periodically for various reasons Sealer does not create a shiny finish or effect slip resistance. It creates a water-tight barrier, strengthens stone, and sometimes adds a “wet-look” which enhances the color
MAINTAINING NATURAL STONE DO seal the area to bring out the color of the stone. DO blot up spills immediately. DO clean surfaces using only a soft cloth or sponge. DO use a stone cleaner DO thoroughly rinse and dry the surface after washing. DO dust mop natural stone floors regularly. DO protect floor surfaces with non-abrasive non-slip mats or area rugs. DON‟T use vinegar, lemon juice or other acid-containing cleaners on natural stone. DON‟T use rough cloths and mops to clean stone floors. DON‟T use vacuum cleaners, as the metal or plastic attachments/wheels may scratch the floor. Dont use cleaners that contain acid such as bathroom cleaners, grout or tub & tile cleaners. Dont use abrasive cleaners such as dry cleansers or soft cleansers. Regular maintenance using the correct techniques and products will ultimately preserve natural stone flooring and reduce the need for very costly refurbishment. The Coliseum in Rome is constructed of travertine and still stands today. The oldest stone floor in Britain, one made of limestone, is around 7,000 years old and still in remarkably good condition. That should be durable enough for anyone.