Natural Stone Fact vs. Myth: Addressing Common Misconceptions

Sponsored by Natural Stone Institute
By Juliet Grable
 
1 AIA LU/Elective; 0.1 IACET CEU*; 1 AIBD P-CE; AAA 1 Structured Learning Hour; AANB 1 Hour of Core Learning; AAPEI 1 Structured Learning Hour; This course can be self-reported to the AIBC, as per their CE Guidelines.; MAA 1 Structured Learning Hour; NLAA 1 Hour of Core Learning; NSAA 1 Hour of Core Learning; NWTAA 1 Structured Learning Hour; OAA 1 Learning Hour; SAA 1 Hour of Core Learning

Learning Objectives:

  1. Compare and contrast the performance of natural stone to artificial materials used in similar applications.
  2. Counter myths around natural stone regarding its cost, maintenance requirements, and sustainability.
  3. Describe the resources and applicable test standards relevant to natural stone.
  4. Explain how natural stone can satisfy green building goals and support overall sustainability of building projects.

This course is part of the Natural Stone Academy

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Common Myths About Natural Stone

While there is little disagreement over the beauty and timelessness of natural stone, there is considerable confusion around its cost, care and maintenance, and sustainability. Let us look at some of the common myths surrounding natural stone.

Myth: It Is Too Expensive

Many specifiers and customers shy away from natural stone because they assume that it is too expensive. While it is true that there are high-end natural stone products out there, the large spectrum of natural stone options on the market ensures that there is a stone for nearly every budget, application, and aesthetic preference. In addition, many natural stone products are in a similar price range as other popular options, such as quartz, large-format porcelain, sintered surface, concrete, and glass.

The price of a given natural stone product will depend on many factors, including demand, availability, and distance from the quarry or fabricator. Incidentally, working directly with a quarry or fabricator can save the client money and gives you a direct line to information about the stone and the company’s practices.

In addition, when you consider the full life-cycle cost of the product, natural stone is not only competitive but also a sound investment because of its durability and longevity. Consider the service life of various flooring products—including ceramic tile, vinyl, and laminates—over a 50-year time span. Natural stone flooring will not have to be replaced in that time and in fact should last at least another 50 years. In that same time span, vinyl may have to be replaced up to three times; in addition, the maintenance costs may be higher. In another example, tile has a comparable lifespan to natural stone, but it requires more maintenance, especially of the grout, which requires regular cleaning and periodic restoration. A life-cycle cost analysis can help you compare the total life-cycle costs of different options—including maintenance, replacement, and disposal—and will ultimately save the client money in the long run.

Myth: It Is Hard to Maintain

Many natural materials require some degree of maintenance. Wood floors, for example, must be swept, cleaned, and oiled to protect them from scratches and stains. Similarly, natural stone requires routine cleaning and maintenance to ensure that it stays as beautiful as the day it was installed. These procedures are not difficult or time consuming; often it is a matter of understanding the products and regimes that are appropriate for that particular stone.

In addition, natural stone can often be repaired, restored, and refinished should a stain, scratch, or etching occur. Most man-made imitations cannot be returned to their original state.

Myth: It Is Not Sustainable

Unfortunately, some people have preconceived notions about the natural stone industry’s practices, with images of vast mining operations that harm workers and the environment and leave gaping holes in the landscape afterward. In fact, quarrying is a well-regulated operation; what is more, the natural stone industry holds a Sustainability Standard for quarriers and fabricators. This along with stone’s naturally low carbon footprint help make it an excellent choice for green building projects.

We will take a deeper dive into the sustainability of natural stone later in this course. Now, let us consider the best practices for the care and maintenance of natural stone.

The Care and Maintenance of Natural Stone

You would not use citrus-based or acidic cleaners to clean a marble vanity. In fact, the most critical factor in properly caring and maintaining natural stone is understanding the stone's geological classification and composition. This information is vital for selecting the best cleaning products and regimes for the particular stone.

That said, there are some general recommendations for cleaning most natural stone products, many of which are applicable to most other materials as well. First, choose a neutral cleaner, stone soap, or mild liquid dishwashing detergent to clean stone surfaces, and avoid abrasive pads. This is a good rule of thumb for all surfaces, not just natural stone, as harsher cleaners and abrasive pads may dull or scratch the finish. Acidic or abrasive cleaners can also damage grout in tile surfaces. In addition, many suppliers offer products specifically formulated for cleaning stone. The manufacturer’s directions should be followed. Use warm water to dilute the product if necessary, as a concentrated solution may leave a film or streaks.

Products that contain lemon, vinegar, or other acids should be avoided, as they may dull or etch calcareous stones. Similarly, scouring powders or creams often contain abrasives that may scratch certain stones. Rust removers should never be used on stone products, as the trace levels of hydrofluoric acid in these products will attack silicates and other minerals.

Cleaning procedures for natural stone, engineered quartz, sintered surface, and tile are similar. A clean rag mop should be used on floors and a soft cloth should be used on other surfaces, such as countertops. The area should be rinsed thoroughly after washing with the soap solution and dried with a soft cloth. The rinse water should be changed frequently. One notable difference between natural stone, engineered quartz, and tile compared with laminates is that laminates should not be flooded with water, as moisture can penetrate the seams and possibly cause delamination. Tiled surfaces also require periodic maintenance of the grout to prevent or remove the buildup of dirt and other materials.

Wet areas have special considerations. Using a squeegee after each use can minimize the buildup of soap scum. To remove soap scum, use a nonacidic soap scum remover or a solution of ammonia and water (about 12 cup ammonia to 1 gallon of water). Frequent or overuse of an ammonia solution may eventually dull the surface of some stone types.

To Seal or Not to Seal

The porosity of stone products varies; some will require more frequent sealing; others may not need to be sealed at all. For some stone products, periodic sealing can help protect the surface from dirt and reduce the incidence of staining; however, there are several factors to consider before breaking out the sealer. The type of stone, its finish, its location, and how it is maintained all need to be considered when determining how to protect the stone.

Impregnators are water- or solvent-based solutions that penetrate below the surface of the stone, where they become repellents. Impregnators are typically hydrophobic (water repelling) and oliophobic (oil repelling). They keep contaminants out without preventing moisture from inside the stone from escaping. Hence, these products are considered “breathable” since they allow the transmission of vapor. Impregnators are recommended for surfaces that frequently contact water and oils—for example, vanity tops and food preparation areas. Make sure the impregnator product is nontoxic and safe for use around food preparation.

Finally, it is important to understand that sealing is not a cure-all for stains. Sealers slow the absorption rate of porous materials; they do not make stone stain proof. Regular use of coasters and trivets and jumping on spills right away will complement the protection provided by the sealing product.

For guidance on sealing and the care of natural stone, visit bit.ly/3eHo48Y.

Special Considerations: Marble

Marble is softer than granite and may be susceptible to scratches and etching. The hardness of marble is comparable to other household materials, including solid surface, hardwoods, and resins in engineered quartz. Because it is a calcareous stone, marble is softer and more vulnerable to stains, scratches, and etching, especially when the surface comes into contact with an acidic substance.

Such common kitchen items as tomatoes, citrus fruits and juices, vinegar, and sodas are acidic. Wine and oils can also cause stains if not wiped up in a timely manner.

Etching and stains can be prevented by the diligent use of cutting boards, trivets, and coasters. Marble countertops should be cleaned regularly, but the product must be appropriate for the material. Mild soaps and stone cleaners are safe choices.

Some varieties of marble may benefit from an impregnating sealer; however, application and maintenance frequency may depend on stone variety and use. It is best to consult the sealer manufacture for specific product recommendations, which can range from every year to every 10 years or more. The surface treatment makes a difference. Polished marble may show etching, while honed surfaces may make etching less noticeable. Refinishing can restore the surface of marble countertops to its original luster; a honed surface can be refinished less frequently. One way to test whether the stone needs resealing is to drop a small amount of water onto the countertop. If it leaves a dark spot after a couple of minutes, the marble needs to be treated.

Natural Stone> The Natural Stone Institute offers a wide array of technical and training resources, professional development, regulatory advocacy, and networking events for the natural stone industry. Learn more at www.naturalstoneinstitute.org/stoneacademy.
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Originally published in Architectural Record
Originally published in April 2021

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