Limestone is a sedimentary rock composed principally of calcium carbonate (calcite) or the double carbonate of calcium and magnesium (dolomite). It is commonly composed of tiny fossils, shell fragments and other fossilized debris. These fossils are frequently visible to the unaided eye on close examination of the stone surface, however this is not always the case. Some varieties of limestone have an extremely fine grain. Pure limestones are white or almost white.

Because of impurities, such as clay, sand, organic remains, iron oxide and other materials, many limestones exhibit different colours, especially on weathered surfaces. Limestone may be crystalline, clastic, granular, or dense, depending on the method of formation. When limestones of any type undergo metamorphism, they re-crystallize as marble. Because all limestone contains calcium carbonate, which reacts with hydrochloric acid to produce bubbles, acid testing is considered one of the most reliable field tests for limestone and calcite mineral identification. Crystals of calcite, quartz, dolomite or barite may line small cavities in the rock. Chert or Flint nodules are common in limestone layers.

The popularity of limestone has varied over the years as a decorating material. In fact, the history of this natural material dates back several thousands of years in ancient Egypt. The reason for its popularity is simple: it is great to work with. Limestone is one of the most versatile and beautiful materials you can use around the home. It is light, neutral, and fits a variety of color design options. It is also durable, making it particularly effective at surviving the abuse of some rooms, like bathrooms and kitchens. You can even use it on the outside where the weather will try to beat it up. Limestone is especially popular in architecture, and many landmarks around the world, especially in North America and Europe, are made primarily of the material.

Bands of limestone emerge from the Earth’s surface in often spectacular rocky outcrops and islands. Examples include the Verdon Gorge in France; Melham Cove in North Yorkshire, England; and the Ha Long Bay National Park in Vietnam. Limestone is readily available and relatively easy to cut into blocks or more elaborate carving. It is also long-lasting and stands up well to exposure. However, it is a very heavy material, making it impractical for tall buildings; it is also quite expensive. Limestone was most popular in the early 20th and late 19th centuries. Train stations, banks and other structures from that era are normally limestone. Limestone is used as a facade on some skyscrapers, but only in thin sheets rather than solid blocks. In North America, most limestone used in construction comes from Indiana.

WHY SHOULD YOU CHOOSE NATURAL STONE?

Natural stone is held in high regard as a premier building material because it reflects unique character, stability, and grandeur. Variations in natural stone’s broad range of color, pattern, and texture are visually interesting and impossible to replicate. And, because it comes from the earth, from eco-friendly compositions, it is a natural choice.

Variety: The diversity of natural stone products encourages limitless design potential. Aesthetically, what you do with stone is as varied as your imagination. Its many factors in the way stone formed within the Earth contribute to its varieties and enhance the innovation it provides, something that cannot be duplicated in a laboratory or come from a mould.

Durability: Natural stone exhibits a durability not found in other building materials. There is an emotional connection to buildings and monuments built in stone that carries a great deal of meaning due to enduring history and a legacy of mankind through the ages.

Green Attributes: Natural stone products like those formed in granite, marble, travertine, onyx, tra-onyx, quartzite, limestone, sandstone, slatestone and others, differently from artifical materials, innate characteristics that contribute toward LEED (Leadership in Energy and Environmental Design) or LEED intended construction. Consider stone’s low embodied energy, ready availability as a naturally occurring material, no off-gases to impair indoor air quality, high thermal capacitance, and exceptional durability for low maintenance and structural permanence. Using natural stone for your projects shows that you care about the environment and consciously strive to preserve it.

Unique: Design projects should stand out and reflect the passion, taste, and personality of the designer. Natural stone is a one-of-a-kind building material that sets you apart from others because it can’t be mimicked, manufactured, or faked.

Value: The value in natural stone is more than a monetary measure. It involves longevity, ease of maintenance, permanence and stability that far exceed initial investment. Utilizing natural stone is now more affordable than ever due to advancing stone quarrying and processing technology that has improved efficiency over the years. New automated machinery allows fabricators to cut natural stone thinner, faster, more consistently and at less cost than in times past. Development of anchoring technologies and systems make installation easier, quicker, and more secure. In addition, natural stone is simple to care for, has an appearance that literally improves with age and can last a lifetime.

NATURAL STONE INSTALLATION INSTRUCTIONS

The proper choice of tools and implements is very important; angle grinder machine or water jet cutting table with diamond blades, notched trowel, spirit level, white rubber mallet, rubber trowel for grouting, cross-spacers for joints and mixing vessels for adhesive preparation etc.

The flatness of the substrate should not be over 5 mm span, therefore must be checked with a 2 meter rule. In case of any flatness defect, the substrate must be re-leveled in order to fix the difference. The substrate must be resistant, stable and totally dry, in order to obtain a correct adherence.

In order to avoid bonding problems, the substrate must be totally clean, free of dust, grease, mortar residues, etc. It is advisable to clean the surface before laying the tiles.

The adhesive type must be chosen in relation to the material absorption and the substrate properties. In any situation, as a precautionary measure, we do not recommend sand mortars use, since sand contains different salts, and when mixed with the cement and water, could be absorbed by the material porosity and may produce pathologies called efflorescence.

For high-absorption materials, like sandstone and limestone, we recommend C1 adhesive for indoor use, and C2 for outdoors. In case of marbles and granites, C2 adhesives can be used in both indoors and outdoors, since the main property of this product is the great adherence and elasticity. In case of natural stone materials with fiberglass or mesh backing, we recommend the use of Type R reactive resin adhesives.

Use a notched trowel to spread the product on the substrate, in order to control the thickness and assure the adhesive distribution all over the surface. For 30x30 cm or larger pieces, it is recommended to use the buttering-floating technique, which consists of applying the adhesive on both the substrate and the back of the tile, in order to ensure a 100% contact with the bonding material.

In order to ensure a total flattening of the grooves left by the notched trowel on the bonding material, lay the pieces and tap them with a rubber mallet. We recommend leaving at least a 1.5 mm. joint between interior pieces and 3 mm for exterior pieces. This is to compensate possible material expansion/contraction caused by temperature variations, of course considering perimeter and structural joints.

The grouting process consists of filling the space between pieces, better known as joints. The installation joints must be clean and free of bonding materials, traces of dirt and grime. This way, adherence of grout will be improved and more effective.

The grouting material should be applied 24-48 hours after the covering application, in order to help the evaporation of the water used to prepare the bonding mixture. This way is possible to avoid moisture stains that might end up causing efflorescence pathologies.

The grouting material should be applied with a rubber trowel and always in the joint gap. Never use the traditional grouting method, which consists of spreading the grouting material all over the coated surface, since the stone porosity can cause scale problems and interfere with the subsequent cleaning.

The removal of grouting material residues must be done not too long after the application. It is necessary to use a damped sponge to avoid leaving grouting material deposits.

In case of laying polished or honed floor coverings, it is advisable to protect the surface until the building work is over. This is mainly not to damage the material and make the cleaning easier.

To carry out cutting procedures in natural stone pieces, it is advisable to mark the pieces with a pencil. To carry out stone drilling, it is necessary to use carbide bits, always beginning with a small diameter until getting the expected result.

NATURAL STONE CARE AND MAINTENANCE

Natural Stone is considered a high quality covering, which fulfills all the physicochemical and building requirements to carry out a good project with demonstrable benefits. One of the main benefits is the low maintenance cost in comparison to other materials like stoneware and artificial stone. The hardness and lifespan of natural stone can be increased with a good election of the material finish, treatment and further maintenance.

Water is the best cleaning solution. However, when it comes to clean and disinfect, it is advisable to use pH balanced cleaners (7-10 pH). Never use aggressive detergents as bleach, ammonia, anti-scaling products, etc. Never use metal utensils that may scratch the surface. In case of stains, try to clean with soapy water first. If the stains persist, proceed with "deep clean" type cleaners available from good manufacturers.

Stain Type and Detergente:

Oils: Water diluted acid solution (vinegar)
Grease: Sodium bicarbonate and warm water
Wine: Water diluted alkaline cleaner
Coffee: Water diluted cleaner*
Blood: Water diluted cleaner*
Ink: Water diluted cleaner*
Paints: Paint remover and plenty of water
Polish: Acetone and plenty of water

* In case of using bleach as cleaning product, this must be water diluted.
* As a general rule, it is advisable to start with low concentrations or maximum dilution. Increase the amount little by little, depending on the results.
* It is important to know that hot water has a higher cleaning potential than cold water.
Remember: Despite the aging, natural stone can always be re-polished to recover its original finish.
Caution: Observe the detergent manufacturer’s precautions and recommended dilutions. Do not use products containing hydrofluoric acid or its derivatives.