Natural Stone Restoration Notes – Harsh Winter Environment Will Harm Marble, Slate, Limestone

The elements and the seasons can be very harsh on natural stone. We at Sungloss Marble Restoration Company concur with that! Possibly the most trying time for natural stone however, is winter. Between the slush, dirt, and freezing and thawing, there is a hazard to stone floors that might get overlooked by some: deicing salts. We recently read an interesting article on the effects on stone of commonly used deicing salts.

The most commonly used product for wintertime deicing is generally known as ‘rock salt’ and it contains—you guessed it—simple salt. Other, more expensive formulations of winter deicing products contain some different chemicals like calcium, magnesium chloride, potassium chloride, ammonium sulfate, and urea. What these chemicals do (in general) is lower the freezing point of water, thus preventing ice slicks in front of your real estate, business, home, bank, or government building. However, when the water soaks into the stone, the dissolved salts and chemicals eventually re-crystallize and that process pressurizes the stone pores. If too much pressure is created—again, you guessed it—the stone becomes damaged in the form of cracks, chips, or spalling.

The article, by Fred Hueston of Stone and Tile Pros, lists one product that is the safest for use around stone: calcium magnesium acetate. The only downside he reports, is the higher cost of this product.

Besides careful selection of deicing products, vigilant protection of stone floors, lobbies, etc., like slate, terrazzo, marble, limestone, granite, concrete, and terra cotta to name a few, is equally important. It is important to clean frequently with a neutral rinseless stone cleaner, and stay up to date with recommended periodic application of breathable impregnating stone sealers, but we also highly recommend carpet runners and floor mats. Floor coverings protect floors from scratches caused by sand and dirt tracked in. In the winter they theoretically can help protect from salty water and debris from soaking into the stone as well, although it is important to keep the mats from getting saturated, and also to lift them and mop underneath to minimize the mat from potentially creating an unintentional source of damage.

If many winters have taken their toll on a surface, Sungloss can help. Our services of wet grinding, honing, polishing, and sealing natural stone can rejuvenate a dull, damaged floor. We can even fill or repair some instances of cracking and spalling stone. It’s something great to look forward to in the darkest, coldest days of winter, besides spring (and baseball)!