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Protection and Maintenance of Natural Stone Floors

FLOORS Traditionally, honed marble was used on floors in commercial and public establishments. A honed finish does not need refinishing as frequently as polished finishes, since foot traffic will dull the polish. In fact, a honed surface develops a patina through wear (honing caused by foot abrasion) that enhances the beauty of natural stone. Polished finishes have long been used in residential applications, but are relatively new to commercial and public applications in the U.S. The use of polished finish on the softer stone varieties can be problematic in high traffic commercial applications. When high gloss factory finishes have been abraded by foot traffic, the resultant effect is normally a non-uniform gloss level, since the abrasion occurs more rapidly in the heavily used portions of the floor. Restoration of this finish can normally be accomplished in-situ, but this is the work of professional contractors specializing in this field. Oftentimes, it is impossible to restore the floor finish to an equal level of gloss as the original product, since the portable equipment used by restoration professionals does not have the same capability as the production line polishers used by the factories. PROTECTION AND MAINTENANCE Two important and separate steps need to be considered: a) initial protection using penetrating or impregnating sealers; b) regular and periodic thorough cleaning using conditioners, polishes, impregnators or sealers, and mild pH 7-9 cleaners specifically formulated for use on natural stone. Products used under both “a” and “b” should be slip resistant when dry: however, when wet, this slip resistance is frequently compromised. INITIAL PROTECTION Despite their high density, some natural stones have a level of porosity that is great enough to allow some staining agents (including the impurities found in the cleaning water itself) to penetrate into the pores to a depth that prevents surficial cleaning methods from removing them. An initial protection with an impregnator and/or sealer will usually lessen this vulnerability. Most manufacturers of specialty chemicals for natural stone offer these two types of protectors to cover all of the different interests of customers and needs of the natural stone:

Impregnators, often also known as penetrating sealers, are designed to penetrate the surface and reside in the subsurface within the first few millimeters of the stone fabric. When properly applied, they will leave no residual coating on the stone’s surface. Impregnators are therefore suited for all surface finishes of natural stone (e.g. polished, honed, and textured). Sealers include topical coatings that bond to the stone surface and provide a sacrificial layer over the stone. Topical sealers are rarely used for natural stone surfaces. Because they are a sacrificial layer, they introduce a maintenance requirement of frequent reapplication, and they also will generally change the appearance of the stone and/or its gloss level.

Manufacturers’ recommendations must be followed in the application of any impregnator or sealer.

Some chemicals may be harmful to the health of occupants and/or the environment. Consult the manufacturer’s recommendations and carefully read corresponding SDS (Safety Data Sheets). Testing in an inconspicuous area is recommended.

REGULAR MAINTENANCE AND THOROUGH CLEANING

Once the floor is properly protected, daily or periodic maintenance becomes easier and the original stone appearance will remain for a longer period of time. Regular maintenance can be achieved by dust mopping, sweeping, or vacuuming when the stone becomes soiled. After all loose soil is removed, the stone may be further cleaned by using a pH neutral cleaner designed for stone cleaning. Using water alone for cleaning may not always be adequate. Water quality is critical, as contaminants contained in the water, such as chlorine, salts, and minerals, may lead to degradation of the stone surface. It is important that the cleaning solution is changed when dirty, and minimal water is left standing on the floor. Maintenance of Honed and Textured Floors Regardless of whether the surface was treated with an impregnator, daily or more frequent dust mopping is recommended to remove harmful particles scratching the surface. Frequent damp mopping, using a pH neutral cleaner, allows you to mop off any surface dirt. Buffing is optional, though it may further improve the appearance of the floor. Periodically, a thorough and deep cleaning may be needed, using a low alkaline cleaner. Consideration should be given to adding a topical coating to honed finishes if a 1.

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NTCA Reference Manual | 2024 / 2025

Chapter 6 | Natural Stone Installations