Care & Maintenance of Natural Stone
A publication from the Marble Institute of America ©
The natural stone you have in your home, office, or commercial building is an investment that will give you many years of beautiful service.
Simple care and maintenance will help preserve your stone’s beauty for generations to come.
This brochure has been developed for you by the Marble Institute of America (MIA) to present routine cleaning guidelines
as well as procedures for stain removal should it become necessary. All methods of clean- ing should be in accordance with ASTM C1515-01.
Know Your Stone
Natural stone can be classified into two general categories according to its composition: siliceous stone or calcareous stone. Knowing the difference is critical when selecting cleaning products.
Siliceous Stone is composed mainly of silica or quartz-like particles. It tends to be very durable and relatively easy to clean with mild acidic cleaning solutions. Types of siliceous stone include: granite, slate, sandstone, quartzite, brownstone, and bluestone.
Calcareous Stone is composed mainly of calcium car- bonate. It is sensitive to acidic cleaning products and frequently requires different cleaning procedures than siliceous stone. Types of calcareous stone include: marble, travertine, limestone, and onyx. What may work on siliceous stone may not be suitable on calcare- ous surfaces.
Finishes: There are three primary stone finishes:
A polished finish has a glossy surface that reflects light and emphasizes the color and markings of the material.
A honed finish is a satin smooth surface with relatively little reflection of light. Generally, a honed finish is preferred for floors, stair treads, thresholds, and other locations where heavy traffic will wear off the polished finish. A honed finish may also be used on furniture tops and other surfaces.
A flamed finish is a rough textured surface used frequently on granite floor tiles.
Many other finishes are available and used throughout the world. Consult with a stone professional if your finish does not match these three primary types.
Lippage: A condition where one edge of a stone is higher than adjacent edges, giving the finished surface an uneven appearance.
Maintenance: Scheduled cleaning, specific procedures, and inspections performed on a daily, weekly, or other regular basis to keep the stone in proper condition.
Poultice: A liquid cleaner or chemical mixed with a white absorbent material to form a thick, stain- removing paste.
Refinishing: Repolishing or honing of dull, once-polished marble, limestone, or granite floors and walls.
Renovation: Cleaning and repolishing of neglected dimension stone surfaces.
Restoration: Large-scale remedial actions taken to restore a structure or area to its original or acceptable “near original” condition. Generally applies to historic structures.
A Note on Historical Buildings
In the case of historically important buildings and land- marks, many of the cleaning, maintenance, and restoration protocols are established by historical preservation committees and other agencies/ departments of the government. Please consult with these organizations when developing your normal maintenance program.
ASSESSING THE STONE’S CURRENT CONDITION
Knowing the current condition of the stone is another critical first step. It is recommended that you develop a checklist of questions to use in your routine examination of the current conditions. Your checklist should include questions such as:
Are the tiles flat and even?
Are there any cracked tiles?
What type of stone finish exists?
Has the stone been coated with any waxes, acrylics, enhancers, or other coatings? If so, which type and manufacturer?
Is there any evidence of staining? What type?
If the stone has been sealed with a topical sealer, are there any signs that the sealer has worn off?
Your answers to these and other questions will help you pinpoint your next step.
Uneven tiles (a sign of lippage) may result in the floor needing to be ground flat, honed, and then polished.
Cracked tiles will allow dirt and other debris to accumulate in the cracks. This may require that the tiles be replaced, or at a minimum, filled.
Knowing the type of stain (organic, oil-based, etc.) will help identify the proper stain removal technique needed. Also, the level of stains or spills the stone can be exposed to will play a role in determining if an application of a sealer is appropriate.
CARE AND PRECAUTIONS
Countertops: General guidelines for both siliceous and calcareous stones: Use coasters under all glasses, particularly those containing alcohol or citrus juices. Do not place hot items right off a stove or out of an oven directly on the stone surface. Use trivets or mats under hot dishes and placemats under china, ceramics, silver, or other objects that can scratch the surface.
For calcareous stones, many common foods and drinks contain acids that will etch or dull the stone surface.
Flooring Surfaces: Many flooring surfaces can become slippery when wet. When wet conditions occur, reduce potential hazards by doing the following:
1. Spread carpeted runners from each outside door into lobbies and corridors to help dry shoe soles.
2. Place bright-colored “slippery when wet” pylons on walking surfaces in conspicuous places.
3. Mop or shovel walking surfaces as often as necessary to remove standing water, ice, and/or snow.
4. Issue standard instructions to building maintenance personnel and prominently post at all janitorial workstations.
5. Follow local building and safety codes.
Dry Treat Stone Care Products
Dry-Treat’s impregnating sealers are technologically different from commonly available silicone, teflon and siloxane impregnators. Our specially engineered molecules penetrate deeper into porous materials and bond permanently inside the pores, without blocking them. This creates a deep barrier of protection within the tiles, paving, natural stone etc, which not only protects against staining, but against other serious damage, such as salt efflorescence. Dry-Treat impregnating sealers stand up to cleaning chemicals, traffic, sunlight, and even commercial cleaning techniques such as high pressure hosing. We back our technology with written performance warranties of up to 20 years, when the sealers are applied by a Dry-Treat Accredited Applicator.