Stone is a high-end building material that can substantially add to the cost of a project. With the help of chemical sealers, the durability of the stone is ensured, and the beauty of the work is preserved. Today, architects can specify a larger variety of stones, knowing that the stones that were avoided in the past due to their brittle or hard-to-clean nature can be strengthened and made stain-resistant with the help of chemical sealers. Sealers invisibly protect stone, forming a barrier to repel stains and water damage.

"When selecting a sealer for natural stone, there are various factors to be considered," said Rod Sigman, Aqua Mix technical services manager. "They include where the stone is installed, hardness, porosity, what look you want to achieve, and the type of surface."

The sealers used on natural stone installations are generally divided into two types: penetrating sealers and coating sealers. "A breathable, pen-etrating or impregnator sealer will help to protect natural stone from below-surface staining," Sigman said. "Impregnators will cost more than the 'standard' penetrating sealers because they repel both water-based and oil-based contaminants and will last longer. Coating sealers are topical and recommended for use on highly porous stone. The sealer fills the crevasses of stones such as limestone, slate, adoquin, shellstone, sandstone and flagstone. This helps reduce ongoing care and maintenance. Reapplication will be necessary depending upon surface traffic."

For installations that are in constant use or see a heavy amount of foot traffic, penetrating sealers are often specified. "A premium high-end sealer is ideal for use on kitchen floors or countertops, in commercial installations with high surface traffic, or where maximum stain protection is required," Sigman said.

These penetrating sealers can help installers achieve a number of different "looks," according to Sigman. "Most penetrating sealer/impregnators pen-etrate into the body of the natural stone and have a natural look with no sheen appearance," he said. "Penetrating sealers with a 'wet look' appearance became quite popular in the mid-90s. Still popular today, these sealers are designed to enhance and enrich unpolished stone such as tumbled marble, slate and travertine. In most cases, coating sealers enhance the surface [of natural stone], leaving a slight sheen."

Aqua Mix offers a number of sealer products for a variety of stone installations. The Aqua Mix Stone Sealer's Choice is a premium, no-sheen, natural look, water-based penetrating sealer/impregnator formulated to provide maximum stain protection, especially in food preparation and serving areas. According to Sigman, this product is recommended for use on all natural stone where a natural look is desired and is equally effective for interior and exterior applications.

The Aqua Mix Water-Based Stone Enhancer is also a no-sheen, water-based penetrating sealer/impregnator. This product, however, is formulated to darken, enrich and highlight the character and beauty of high-porosity, unpolished natural stone, according to Sigman. It also rejuvenates the color and improves the appearance of unsealed, worn and weathered porous stone. Also recommended for both interior and exterior applications, this stone enhancer can be used on unsealed, unpolished porous natural stone such as slate, tumbled marble, sandstone, cantera stone and flagstone.

A specially formulated water-based blend of acrylic polymers, the Aqua Mix Slate Sealer provides both a stain-resistant surface seal and a durable low-sheen finish. This product allows moisture vapor transmission and is not affected by ultra-violet light. It is recommended for use on slate, sandstone, flagstone, adoquin and cantera stone.

ProSoCo has introduced a number of sealant products for stone care as well. Sure KleanR Weather Seal SL100 and SL20, members of the Weather Seal family of products, are used to protect concrete, brick and masonry. SL100 water repellant, a neat silane system that offers invisible protection and low volatility, is also VOC compliant. According to the company, the small molecular structure of SL100 ensures maximum penetration and colorless protection of dense, color-sensitive surfaces. The absence of a solvent carrier in this product enables applicators to achieve two to four times the coverage rate normally achieved with solvent-reduced protective treatments. Depth of penetration is controlled by the application rate.

SL20, a ready-to-use, high-grade silane water repellant, weatherproofs exterior masonry by preventing moisture intrusion in the porous substrates. Treated surfaces resist the damaging effects of freeze/thaw cycles, acid rain and salt formation, the company reports. Sl20 reduces efflorescence, mildew and the stains caused by atmospheric dirt and pollutants. It reacts to form a bond within the substrate, creating a repellent barrier without surface film or gloss, while allowing the stone to retain its natural vapor permeability.

Dedicated to preserving the quality image of the marble stone and tile industries, Miracle Sealants Co. has shown that properly maintained stone and tile surfaces can last forever. Miracle Sealants has focused much attention on product development in the laboratory, testing and refining each new product. The company has also stressed the importance of educating others in the proper care of these elegant surfaces.

Miracle Sealants's product line includes 511 Impregnator and 511 Porous Plus - both natural-look penetrating sealers - and 511 H2O, a water-based penetrating sealer. The 511 Impregnator is a unique polymerized silicone formulation designed for the protection of medium to dense porous tile, stone and grout surfaces. Penetrating into the surface, 511 Impregnator forms an invisible barrier that is resistant to moisture and stains, while allowing vapor to escape. According to the company, this sealer is UV transparent, resists acid rain and will not yellow under any circumstances.

Miracle Sealants's 511 Porous Plus is designed for the protection of all porous tile, stone and grout surfaces. Like 511 Impregnator, the 511 Porous Plus resists stains and moisture and is not a surface coating so it will not alter the stone's natural look. Both of these sealers can be used in both interior and exterior applications and will be dry to the touch in one to three hours after application. The 511 Impregnator is suggested for sanded grout, porcelain tile, concrete, slate, quarry tile, polished granite, brick, quartz, ceramic tile, polished marble, travertine, glazed tile, terrazzo, stucco and agglomerate. The 511 Porous Plus is intended for sanded grout, terra-cotta, cantera/adoquin, brick, limestone, sandstone, cement, slate, saltillo tile, flagstone, concrete tile, precast concrete, flamed and honed granite, honed or textured marble and other porous surfaces.

The water-based penetrating sealer, 511 H2O, provides water and stain protection for natural stone, tile and grout surfaces. This odorless and oil-resistant product is easy to use, and it covers 500 to 3,000 square feet per gallon. The 511 H2O is suggested for either interior or exterior applications on surfaces such as grout, granite, saltillo tile, brick, quarry tile, marble, slate, concrete, ceramic tile, limestone, flagstone, glazed tile, terrazzo and travertine.

New and innovative technology in the tile and stone industry has also been introduced by Stone Tech ProfessionalT. The company's flagship sealer, Impregnator ProT, is a fluoropolymer sealer which provided the industry with an alternative to the more traditional silicone sealers that were available at the time of its development in 1996, according to the company.

Impregnator Pro is a solvent-based sealer that repels oil-based stains in addition to water damage. "Impregnating subsurface sealers work by lowering the critical surface tension of the stone," the company reports. "The lower the surface tension the better. Lower surface tension means greater liquid repellency."

Stone Tech Professional recently released a new product called BulletproofT, which was designed to provide the special treatment required by some porous stones. This solvent-based stone protector is suggested for stones such as Juparana granite or other gneiss granites, limestone, concrete and other porous stone. "With the increasing use of stone in homes and commercial buildings, identifying and properly sealing these porous stone surfaces ensures customer satisfaction with their stone investment," the company states.

A water-based fluoropolymer sealer called Porous ProT was developed by Stone Tech Professional for applications where a solvent-based product may not be appropriate. This impregnating sealer repels oil as well as water and is particularly suited for porous stone and masonry surfaces, as well as areas in which odor or VOC emissions are a concern. According to the company, Porous Pro is often used on driveways that could potentially be ruined by oil stains from vehicles and installations such as terra-cotta tiles, where a matte finish is preferred.

For areas where oil is not a concern, Stone Tech Professional offers Water BlockT and Water Block-SBT, which are appropriate for installations where there are concerns with efflorescence, mold growth and other moisture-related issues, according to the company. Both of these products are resistant to UV and sunlight exposure, chlorine and weather effects, and they come in water- and solvent-based formulas.

Stone Tech Professional also offers a line of sealers designed to enrich the appearance of the surface being sealed. Formulated in both solvent- and water-based versions, EnhancerT Pro and Enhancer Pro-WBT provide both color enhancement and sealing in one product.

HMKR has offered a comprehensive line of quality stone care products for more than 25 years, the company reports. The HMK Stone Care System consists of a variety of products including cleaners, impregnators, sealers, and maintenance products specifically developed to preserve the integrity of stone installations.

HMK's S32 Water-based Impregnator provides protection against water, dirt, oil, and grease absorption. It is used for interior and exterior use on absorbent natural stone, unglazed tile and manmade hard-surfaces, and is best suited for honed and textured surfaces. Treated surfaces remain highly vapor permeable after the application of this sealer, which is UV resistant and leaves a natural appearance. Since S32 is solvent-free, it can be applied in public areas, such as lobbies, hospitals, shopping centers, supermarkets, etc., while still occupied, the company reports.

The S34 Silicone Impregnator from HMK has a high stability against dirt, water, oil, and alkali infiltration. Its suggested uses include interior and exterior applications of natural and cast stone, regardless of the surface's finish. S34 is UV resistant, or non-yellowing, and leaves a natural appearance with little or no color change and no build-up or shine. Treated surfaces remain 98% vapor permeable. According to the company, this product provides excellent protection for countertops, vanities, floors and showers. S34 is the company's most widely used sealer for both residential and commercial installations.

A modified silicone/acrylic base sealer, HMK's S35 Stone Sealer with Matte Finish is formulated to produce a tough, hard, and highly protective finish. S35 protects against water, dirt, and oil infiltration and is used for both interior and conditional exterior applications on honed and textured mineral surfaces. S35 enhances the stone's color and texture, while leaving a matte finish. It is highly vapor permeable, UV resistant, and slip retardant, and is often used on slate, tumbled marble, limestone and thermal granite installations to enhance the natural color and beauty of the stone.

HMK's S37 Stone Sealer with a Satin Finish is also a modified acrylic base sealer that produces a tough, hard, and highly protective finish. S37 protects against water, dirt, and oil infiltration, and is suggested for interior use on honed and textured mineral surfaces. S37 enhances the stone's color and texture, leaving a satin finish. Like HMK's S35, this product is highly vapor permeable, UV resistant, and slip retardant and is often used on slate, tumbled marble, limestone and thermal granite installations.

For a high-gloss finish, HMK offers S39 Stone Sealer - High Gloss. This modified acrylic-based sealer also produces a tough, hard, and highly protective finish, which protects against water, dirt, and oil infiltration. This product, however, is for interior use only, on rough and textured mineral and some ceramic surfaces. S39 enhances the stone's color and texture, leaving a high gloss finish, and is highly vapor permeable, UV resistant, and slip retardant.

A sealer for porous stones and concrete is available from Bonsal. Known as Concrete & Masonry Sealer, this product can be used on poured, pre-cast, tilt-up and pre-stressed concrete, as well as stucco, brick, coral, limestone, plaster, block, drywall, concrete roof tile and other stone applications. Bonsal's sealer is resistant to alkali, stains, abrasions, gasoline, oil, salt, mildew and UV rays. It is non-yellowing, and it reduces the potential for efflorescence while allowing moisture vapor transmission. Suggested for both interior and exterior applications, this sealer is tintable to improve minor color variations in stone surfaces and is VOC compliant. It can be applied by brush, with a hand pump or with an airless sprayer, and it will cure after 24 hours as long as the humidity is less than 50%.

Professional contractors understand that their reputation depends not only on the quality of an installation, but also on its appearance and durability over time. Custom Building Products offers technologically advanced, professional products designed specifically to enhance the beauty and assure the long-term integrity of a tile or stone installation.

SurfaceGardR Penetrating Sealer with TeflonR Surface Protector, part of the TileLabR line of tile and stone care products, ensures that a tile or stone installation maintains its appearance by protecting it from stains for years to come, according to the company. This stain barrier provides maximum effectiveness against oil- and water-based stains. Custom Building Products has recently improved the formula with Teflon Surface Protector, which repels grease, dirt and other contaminants by reducing their ability to adhere and penetrate into the surface, the company reports. This sealer can be used on all types of natural stone, including marble, limestone and granite as well as saltillo pavers, concrete, unglazed tile, brick and masonry. It is suitable for both interior and exterior use, and is particularly effective in high-traffic or food preparation areas where maximum protection is required.

For enhancing the surfaces of stone installations while protecting them from stains and water damage, Custom Building Products offers several sealers that enrich the finish or color of the stone. Gloss Sealer and Finish is a clear, high-gloss, protective surface sealer and finish designed for saltillo, terra-cotta, quarry tile, slate and flagstone. It seals the surface to resist stains, dirt and grease. According to the company, this product not only beautifies and enhances the surface, but it provides resistance to scuffs, marring and scratches. This water-based acrylic finish has low odor and will not yellow with age.

Matte Sealer and Finish by Custom Building Products is also a surface sealer for saltillo, terra-cotta, quarry tile, slate and flagstone. It enhances the beauty of the stone while leaving a soft matte sheen that reduces scuffs, marring and scratches. This water-based product is designed for both interior and exterior use.

Also from Custom Building Products is Stone Enhancer and Sealer. This color enhancer and penetrating sealer enriches and highlights the color and texture of a variety of natural stone and grout. It rejuvenates the color and appearance of worn, faded stone, tumbled marble and other rustic-looking stones. Stone Enhancer and Sealer can also be used to darken the color of grout, giving it a wet look, the company reports. Providing long lasting protection against oil, grease and stains, this sealer is created with a water-based, non-yellowing, low odor formula that can be used indoors and outdoors.

An array of sealant products is also available from Akemi, including surface sealers, impregnators and stain repellants. Akemi Stone Sealer creates a colorless, non-yellowing acrylic coating that seals pores and absorbent surfaces. Sealing the stone makes it easier to maintain, as the coating provides long-term protection against dirt. Stone Sealer contains solvents and high-grade acrylic resins and comes in either satin or matte finish.

Akemi's Stone Impregnator penetrates deep into the stone, making it waterproof without impairing vapor permeability. According to the company, this product protects stone facades from driving rain and is an efficient dirt repellent.

With a special formula to repel water, grease and oil from stone surfaces while still allowing the stone to breathe, Akemi's Stain Repellent was specifically created to protect floors, table tops and work surfaces. This product is safe for use in areas where food is prepared, and it can be used outdoors as well as indoors.

Since its founding in 1937 in Italy, Bellinzoni has manufactured a range of products, which now includes more than 40 products and specialty items for cleaning, polishing and protecting marble, granite and other types of stone. One of the company's featured products is SuperBlock, a silicone-based impregnator that water-proofs and protects marble and granite from driving rain, dirt and contaminants, while allowing the stone to breathe.

Perfect for countertops, UltraSealer from Bellinzoni is a water-based impregnating sealer which blocks and helps protect marble and granite from water, oil and grease stains. Excellent on honed material, UltraSealer contains no solvents and provides a high degree of waterproofing, the company reported.

UltraColor, a color enhancer and topical sealer from Bellinzoni, is a mixture of waxes and sealers that brings out the deep color of natural stone and creates a satin finish. This product is suggested for use on slate, tumbled marble and flamed granite, but is not for use on polished stone.

Used to seal and strengthen very porous materials, such as travertine, sandstone and limestone, Bellinzoni's Sigil Fix also acts as a repellant against oil, grease and water. Sigil Lux can be used in conjunction with Sigil Fix to complete the sealing process. This product acts as a topical sealer and polish by giving the treated material a slight stain sheen. Both of these products will enhance the natural beauty and color of stone, according to the company.

Founded with the primary goal of providing safe and effective stone and ceramic maintenance chemicals and procedures, Stone Care International currently educates stone consumers and those in the stone industry to use the correct procedures and materials to preserve the integrity of stone. Under-standing stone and the products that are available for stone care are vital elements for a successful stone maintenance system, the company reports.

One of the products Stone Care International has devised for sealing stone surfaces is the water-based Aquapel Penetrating Sealer. This below-surface sealer protects the interior of natural stones as well as masonry, stucco, concrete and sanded grout. It has a special blend of polymers and resins that bond to the stone and create a water- and oil-repellant membrane to prevent staining, yet it allows the stone to breath and release moisture vapors, according to the company. Ideal for interior or exterior usage, Aquapel Penetrating Sealer is UL classified for slip resistance.

Stoneguard penetrating sealer, also from Stone Care International, protects the interior of the stone from staining and prevents adhesion to the stones surface. This product is recommended for both interior and exterior installations. It prevents contaminants from absorbing in and still allows the stone to breathe and release moisture vapors, protecting against both water- and oil-based stains.

Glaze 'N Seal also offers a range of products for sealing stone. The company's Slate Sealer is designed to protect and beautify slate, flagstone and quarry tile. It is a fast drying, low-gloss, water-based product, which can be used indoors and outdoors. Slate Sealer repels oil and grease with no harmful vapors, and it cleans up with water.

Stone Sealant, a water-based stain resistant impregnator by Glaze 'N Seal, allows stone surfaces to maintain their "natural look." This product does not use harsh solvents and will not change the appearance of the stone in any way, the company reports. It is safe to use on all fine stone, including marble of any finish, granite, limestone, travertine, onyx, quarry tile, concrete tile, saltillo tile, porcelain, slate, terrazzo, stucco, brick, flagstone, terra cotta, cantera and masonry. Glaze 'N Seal's Stone Sealant is non-slip and resists mildew and mold.

Careful research over the last few years, along with experience in the field of marble restoration, have given Delta Research the opportunity to develop a range of product treatments to treat any stone surface, from polished marble to terra-cotta. The company offers several sealants including Quasar, Stop Damp, Stone Coat, and Stone Wet. Quasar, an anti-stain treatment for polished marble and granite tops, protects the surface from various staining substances without leaving any type of film or artificial substance on the stone. It will protect against stains caused by food and drinks such as coffee, and the treatment will not alter or change the natural color or aspect of the stone. Perfect for installations such as tables, countertops, vanity tops, shower units and bath surrounds, Quasar will protect against many types of stains, excluding acid substances, Delta reports.

The Stop Damp anti-stain treatment is suitable for the protection on polished marble and granite flooring. Treating floors with Stop Damp helps to avoid major stains and shadows from rising through or appearing on the surface of the stone. This product also prevents stains caused by rising humidity, salts and cement based grouts. Stop Damp is formulated to prevent the yellow-brown stains appearing in the stone caused by the natural chemical reaction to dampness and general water cleaning mainten-ance, and the treatment will not alter or change the natural color of the stone or leave any type of surface film.

Stone Coat was specifically developed to overcome the problem of dirt caused by heavy foot traffic in public places such as shopping centers or residential entryways. In these situations, the natural stone may have superficial open pores in which the dirt can ingrain itself and make it extremely difficult to clean and to remove, the company stated. Stone Coat closes those superficial pores, giving the surface a natural satin effect finish with a high resistance to traffic. Stone Coat is easily cleaned with neutral detergents and is easily applied and maintained, according to the company.

Stone Wet treatment gives honed, tumbled, sandblasted, hammered or natural stone floors a natural wet look and enhances the color of the stone. Stone Wet is not a varnish and does not leave patches or undesirable artificial effects on the stone surface. The treated floor can be cleaned and dry-buffed, and the treatment will be more effective as time goes by, Delta reports. This product does not yellow, and it has a good resistance against usage.

The benefits of sealing natural stone installations are numerous. Without sealer to preserve the integrity of a quality stone installation, the hours put in by the installers, and the money spent by the consumers would all be for naught. This finishing touch provides the protection necessary to keep the stone looking like new and can also add another dimension to the surface appearance of the stone. "Sealing helps to resist staining and reduce ongoing maintenance requirements," Sigman said. "It will also help preserve and enhance the original appearance of the stone."