Comparing the performance attributes of natural stone with manmade materials

Interior Design

Styles may change from season to season, but Mother Nature creates unique designs in natural stone that are historically innovative and always on trend. This is why natural stone remains a timeless and flexible option for many interior applications including countertops and flooring. The variety of natural stone available is also beautiful, durable, and versatile, offering endless possibilities for interiors.

Manmade materials often attempt to emulate or replicate these characteristics and qualities. It is essential to understand how natural stone compares to some of the manmade materials used for the same applications in order to select the most appropriate material. It is also important to know how the material chosen for an interior project will perform under a variety of circumstances, conditions, and uses. At the same time, knowing how the material impacts the environment will ensure that you are choosing the most sustainable material for the application.

Coastal Sand limestone. Photo courtesy of MSI.

Performance Matters

A material’s optimal performance is based on a combination of the attributes of the material itself, how the material is installed, and the conditions to which it is exposed. There are many different issues to consider for interior applications:

• How will the material react when it is exposed to heat and elevated temperatures? Some materials will scorch, while others may crack if they are heated too rapidly or unevenly.
• Can the material withstand exposure to chemicals without a visual change or performance degradation? Exposure to acids or alkali, quite common in kitchens, can potentially cause etching.
• How stain-resistant is the material? It is important that the material does not stain easily and that stains can be removed easily. Materials with lower absorption rates tend to be more stain-resistant. Using a sealer on more porous materials can lower their absorption rate, helping them to perform better and be more stain-resistant.
• Is the material slip-resistant? Slip-resistance is the level of traction needed for a walking surface to remain safe for those using it. The texture, porosity, surface treatments, and elements including water, dust, and a build-up of cleaning product residue can alter the slip resistance of the material. Slip resistance is impacted by the material’s texture and porosity, as well as any surface treatments used and elements it is exposed to

Performance attributes should be addressed no matter what material you are considering or what type of project you are working on. These factors play an even more important role in sustainability and in the long-term performance of the material. Let’s look at how natural stone compares to some manmade materials from the perspective of these performance objectives.

Saratoga soapstone. Photo courtesy of Stone Store.

Interior Applications for Natural Stone versus Manmade Materials

Countertops

The possibilities for countertops using natural stone are quite extensive. Granite, quartzite, marble, and soapstone are among the many options to consider for these hardworking elements in a kitchen or bath. Every natural stone slab connects directly to nature as a piece of Earth’s history. These stones are versatile, meaning they can be cut and finished into different shapes and patterns, and with various finishes, creating a cohesive aesthetic. There are typically more options for edging and surface textures available for natural stone than manmade surfaces. Because most stone is formed in nature through extreme heat and pressure, natural stone is inherently heat resistant. Granite and quartzite are also very durable and scratch resistant. Marble is particularly prized for its beautiful veining, although it may be susceptible to etching. Although soapstone can scratch easily, it can also be easily repaired. Some stones are porous which may cause the material to stain over time. Sealers are recommended for most applications.

In some cases, natural stone may cost more than manmade materials initially—but often, natural stone proves to be the most cost-effective choice due to its durability.  This is especially true because natural stone can also be refinished, repaired, restored, or recycled.  Stone also has a low embodied energy, an important consideration for sustainability requirements. This is because natural stone was created by the Earth and very little energy or additional resources are needed to quarry, fabricate, and finish it.

Manmade materials including engineered quartz, porcelain, sintered surface, acrylic/solid surface and cultured marble are also options for interior countertops.  These materials typically do not need to be sealed. The patterns and colors of manmade materials are usually consistent within the same dye lot. Acrylic/solid surfaces are repairable, but it is often expensive to do so. Most of these materials do not last as long as stone. Porcelain can be more expensive to purchase and is more expensive to fabricate than natural stone. It is also difficult to repair since the patterns are not full bodied. These materials are typically made in thinner formats which also reduces the edge selection options. This results in the edges not having the same texture and pattern as the surface. The synthetic components of engineered quartz can break down when exposed to UV light. Acrylic, engineered quartz, and cultured marble are not heat or UV resistant. Variation between batches of manufactured materials may cause installation or customer service issues.  Most of these materials also have a high embodied energy because they require a wide range of other materials and energy intensive processes to be manufactured.

Photo courtesy of Coldspring.

Flooring

Natural stones including granite, travertine, limestone, marble, and slate are good options for flooring.  Again, one of the main performance aspects of using natural stone in this manner is its incredible durability. Design options abound with more edge treatments, surface texture, and color than most manmade materials. Most textures are slip-resistant and most natural stones are also UV resistant. Natural stone also comes in a variety of thicknesses and is easy to care for once properly protected.  They will also maintain their color and patina nicely over time if maintained properly.  In some cases, natural stone will cost less than porcelain or concrete imitations.

There are a few other issues to consider. Polished finishes may require a topical treatment to increase the slip resistance. Marble, limestone, and travertine can etch when exposed to acidic substances. Stones that have higher absorption rates will need to be sealed. Once again, the low embodied energy of natural stone makes it a great option for meeting sustainability goals. As previously mentioned, natural stone’s long life cycle makes it a very cost-effective choice.

Porcelain, ceramic, concrete, and terrazzo and plastic-based materials such as laminate and vinyl are among the most popular manmade flooring materials. A few of the pros of using these materials include the durability of ceramic and porcelain. Additionally, ceramic, porcelain, and vinyl are easy to care for. There are usage ratings available for specific applications, which helps make it easier to select the right option for the use you are considering. Terrazzo is a creative material because of the custom options available in production. Laminates are generally inexpensive while porcelain is more expensive than ceramic and other popular flooring materials.

There are a number of cons to using these materials. Porcelain is a heavy and unforgiving material, so specialized equipment is needed to cut it. The density of porcelain often requires that sub-floors and supports are strong enough to withstand the extra weight. These issues can also add to the cost of installation.  Most manmade materials are only manufactured in thinner formats and the edges do not have the same texture or pattern as the surface. Their patterns and sizing are limited and they typically cannot be refinished. Porcelain and ceramic are susceptible to chipping and laminates and vinyl can be easily scratched or indented. Laminate and vinyl also require adhesives that off gas, and laminates are not moisture resistant.  There will be variances across color between batches or lots of the materials. Many of the petroleum-based materials contain chemicals that are toxic, including those marked as Red List chemicals. These products also have high embodied energy, which creates a negative impact on the environment.

Galaxy Grey granite. Photo courtesy of Artistic Tile.

Natural Stone and Sustainability

Natural stone has demonstrated considerable durability in local and regional environments and applications. In many cases, these have lasted for hundreds of years, even millennia. Most of the manmade materials have not been around long enough to demonstrate that level of performance. The qualities of longevity and durability have proven that natural stone is a great choice for also meeting green building goals. The initial material and installation costs are off-set by the long life expectancy and the low maintenance requirements. Little to no cleaning or chemicals are required to maintain the material and as mentioned, natural stone can also be refinished, repaired, restored, or recycled. Natural stone is 100% natural stone. Engineered quartz, concrete, and porcelain require many different materials including chemicals to be manufactured and many of them are not recyclable.

So, as Oscar Wilde once said: “Imitation is the sincerest form of flattery that mediocrity can pay to greatness.” Choose natural stone and you will be contributing to the long legacy of great, high-performing, sustainable projects in the world.

Danby marble. Photo courtesy of Stoneshop.

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Comparing the performance attributes of natural stone with manmade materials

Exterior Design

While design trends come and go, natural stone remains a timeless and flexible option for many exterior applications including cladding, paving, and hardscapes. This is due to the variety of natural stone types available that are beautiful, durable, and versatile. No wonder so many manmade materials try to emulate or replicate these characteristics and qualities.

It is important to know how the material chosen for an exterior project will perform under a variety of circumstances, conditions, and uses. It is also essential to understand how natural stone compares to manmade materials used for the same applications in order to select the material that will perform the best. At the same time, knowing how the material impacts the environment will ensure that you are choosing the most sustainable material for the application.

Photo courtesy of Connecticut Stone.

Performance Matters

A material’s optimal performance is based on a combination of the attributes of the material itself, how the material is installed, and the conditions to which it is exposed. There are many different issues to consider:

• How will the material hold up under freeze/thaw conditions? Continued cycles of freezing and thawing can cause some materials to degrade more quickly.
• Does it have good UV resistance and solar reflectance? Many materials will break down over time or change appearances when exposed to UV light.
• Does the material have a low absorption rate? Materials with lower absorption rates tend to be more stain resistant. Sealing a material can lower its absorption rate and improve its performance.
• Is the material slip-resistant? Slip resistance is the level of traction needed for a walking surface to remain safe for those using it. Slip resistance is impacted by the material’s texture and porosity, as well as any surface treatments used and elements it is exposed to, including water and dust.

Performance attributes should be addressed no matter what material you’re considering or what type of project you’re working on. These factors play an even more important role in sustainability and in the long-term performance of the material. Let’s examine how natural stone stacks up to manmade materials from the perspective of these performance objectives.

Photo courtesy of Gallegos.

Exterior Applications for Natural Stone versus Manmade Materials

Cladding and Veneer
The possibilities for natural stone cladding and veneer are endless. Limestone, granite, marble, travertine, basalt, slate, quartzite, and sandstone are among the many options. These stones are versatile, meaning they can be cut and finished into different shapes, textures, and patterns, creating a cohesive aesthetic. Many stones are durable in extreme weather conditions. When discussing vertical stone applications, the installation standards and techniques can make even vulnerable stones durable. Most stones have a long life span. Light colored stones have a high solar reflectance index, meaning they will reflect the sun well, reducing heat gain on the building or site. Stone also has a low embodied energy, an important consideration for sustainability requirements. This is because natural stone was created by the Earth and very little energy or additional resources are needed to quarry, fabricate, and finish it. Some stones are porous and may stain if subjected to contaminates over time. Depending on the stone’s mineral composition it may be susceptible to the effects of acid rain. Natural stone may sometimes have a higher initial cost than manmade materials, but it often proves to be the most cost-effective choice because it lasts so long. This is especially true because natural stone can also be refinished, repaired, restored, or recycled.

Manmade materials including porcelain, concrete, GFRC panels, metal, and terracotta are also options for exterior cladding.  Concrete and porcelain are durable and UV stable; good choices for the exterior and the exposure to sunlight and the elements they must withstand. However, these materials do not typically last as long as stone. Concrete, in the form of cast stone and cultured stone, is often tinted and can fade heavily from sunlight/UV exposure. Some manufacturers are improving the color fastness of cultured stone, but that adds chemicals and cost to the final product. Some manmade materials can also sometimes look flat since they are often made to be uniform in appearance and lack the natural veining and textures of natural stone. Most of them also have a high embodied energy because they require a wide range of other materials and energy intensive processes to be manufactured.

Paving
Natural stones including granite, sandstone, basalt, limestone, slate, travertine, marble, and porphyry are good options for paving. Again, one of the main performance aspects of using natural stone in this manner is its incredible durability. Surfaces can also be finished for slip-resistance and design options abound with more edging, pattern, surface texture, and color than manmade surfaces. Many natural stones perform very well in freeze/thaw environments and conditions. In some cases, natural stone will cost less than porcelain or concrete imitations. Once again, the low embodied energy of natural stone makes it a great option for meeting sustainability goals. The installation of natural stone may be more costly than some manmade materials and it may need to be sealed, depending on the type of stone, location, and environmental conditions. However, as mentioned previously, natural stone’s long life cycle makes it a very cost-effective choice.

Concrete, clay, and porcelain are among the manmade materials used for paving. A few of the pros of using these materials include the possibility of lower replacement and maintenance costs for concrete, and that porcelain is UV stable. There are limited texture options for concrete, which can contribute to a lower cost for the material. Quite often though, concrete fades and the material takes on a very aggregate-like appearance and will lose its color. New technologies are improving surface wear, color fastness, texture, and stain resistance. However, these add quite a bit to the cost and in some cases will make it more expensive than natural stone. For clay, the use of sand mold and wire cut production methods will yield a paver that has a high absorption rate and may have significant issues with salts and efflorescence. These pavers require a more costly installation process due to their larger sizing tolerance issues created by the moisture and firing process. There are pavers created with a compressed production process which perform better but still have performance issues and are not as durable as most natural stones.  High fired or vitrified clay pavers can be very hard and durable, but also very brittle. Porcelain behaves like glass and can also be very brittle, especially in a dry set application in a freeze thaw environment, so it will need to be set with spacers to protect itself in the winter. Porcelain has no absorption, so water will just sit on the surface. The water needs to evaporate or surface drain, so in the winter this can create a very slick surface and be dangerous. These products also have high embodied energy, which creates a negative impact on the environment.

Eden limestone dimensional flagstone. Photo courtesy of Lurvey Supply.

Natural Stone and Sustainability

Natural stone has demonstrated considerable durability in local and regional environments and applications. In many cases, these have lasted for hundreds of years, even millennia. Most manmade materials have not been around long enough to demonstrate that level of performance. The qualities of longevity and durability have proven that natural stone is also a great choice for meeting green building goals. The initial material and installation costs are offset by the long life expectancy and low maintenance requirements. Little to no cleaning or chemicals are required to maintain the material and as mentioned, natural stone can also be refinished, repaired, restored, or recycled. Natural stone is 100% natural. Engineered quartz, concrete, and porcelain require many different materials including chemicals to be manufactured and many of them are not recyclable.

So, as Oscar Wilde once said: “Imitation is the sincerest form of flattery that mediocrity can pay to greatness.” Choose natural stone and you will be contributing to the long legacy of great, high-performing, sustainable projects in the world.

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Precast concrete is a popular building material that is cast in a mold or form. This process is done off-site from a project to control the product quality and reduce waste. The material is used in both indoor and outdoor projects for wall panels, flooring, and even kitchen countertops. Gray is often the color choice for concrete products, but there are several color options available that are achieved through the use of dyes, pigments, and acid stains.

Some of the ingredients in precast concrete are natural materials, such as coarse and fine aggregates, cement, water, and admixtures. The concrete industry has made efforts to reduce their significant environmental impact by substituting some of these ingredients with fly ash, a byproduct of coal production. Because they are achieving a reduction in the embodied carbon with this strategy, they often market their products as “green.” There are a few sustainable characteristics to precast concrete including its thermal mass. The factory environment uses less material than concrete created on site and often the materials come from local sources, which can reduce transportation costs and emissions. However, as you can see from the manufacturing process outlined below, the multi-step and energy intensive processes involved in manufacturing precast concrete create a much larger environmental footprint than natural stone.

A precast concrete wall panel with a repeating pattern. Photo Credit: Wikimedia Commons/ Acabashi

Manufacturing Precast Concrete vs. Natural Stone

To manufacture precast concrete, raw materials are required to first make cement. Minerals are mined out of the ground and then transported to a cement manufacturer or plant. The minerals are heated at extremely high temperatures to create the cement which requires the use of a lot of energy and produces a significant amount of harmful emissions including sulfur dioxide, nitrogen oxide, and carbon monoxide. A mold and steel reinforcement are also needed for the precast concrete. The mold must be created and the steel must be acquired and transported to a steel manufacturer, where it is melted and cast into reinforcing rods. Aggregates are also required, which must be mined, crushed, and sorted. There are other additives and products required depending on the desired finish. The materials are mixed with water, put into molds, and cured into the final product. Polishing, sealing, and/or waxing may also be necessary, depending on the end use of the precast concrete.

In contrast, natural stone requires only quarrying, fabricating, finishing, and transporting. No additional materials or chemicals are required to create natural stone. The Earth naturally forms the material over time. This means natural stone really is a natural material and has many other attributes, including its durability, recyclability, and wide range of aesthetics. Natural stone can be used in many different indoor and outdoor applications as well and contains no Volatile Organic Compounds (VOCs), meaning it does not emit any harmful gases, making it a healthy material.

Sustainability Concerns

From an overall sustainability perspective, natural stone has a lower environmental footprint than precast concrete. This is due to the minimal resources used to quarry, fabricate, finish, and transport natural stone.  As the graph below demonstrates, precast concrete has a higher global warming potential (GWP) than natural stone. Every step in the precast concrete manufacturing process requires the use of a lot of energy, which contributes to their total GWP. The larger the GWP, the more that a given gas warms the Earth compared to carbon dioxide (CO2) over the same timeframe. The natural stone industry is often criticized for utilizing raw materials that are not rapidly renewable. However, natural stone is abundant within the Earth. Other industries also utilize the supply of natural stone as it is a significant ingredient in concrete, porcelain, and other manmade products.

The impacts of these processes have been documented and systematically compared against other materials using the same environmental criteria. This information is a valuable resource when selecting a sustainable material for a project.

The embodied carbon quantities displayed were estimated based on the following:
Unite of Measure: Global Warming Potential (kg CO₂ eq)
Functional Unit: 1m²
Scope: Raw Material Extraction, Transportation, Manufacturing (A1-A3)
Natural Stone: Industry-Wide EPDs for Cladding, Flooring & Countertops
Pre-Cast Concrete Cladding: Industry-Wide EPD for Architectural Precast Panels, 150 lbs per ft3, 4” thick
Engineered Quartz: Average of three individual manufacturer EPDs
Terrazzo: Average of three individual manufacturer EPDs

These characteristics and attributes also make natural stone a great choice when seeking a green building rating certification within the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) or the International Living Future Institute’s Living Building Challenge (LBC). The different manufacturing processes and impacts of building materials are being documented in product labels such as Environmental Product Declarations (EPDs) and Health Product Declarations (HPDs). These labels make it even easier to qualify for points and credits within LEED and other green building rating systems using natural stone. The labels document and quantify environmental information on the life cycle of a product and allow you to make comparisons and informed decisions on materials that fulfill the same function. The product labels are also intended to demonstrate that the health and environmental claims are transparent, accurate, and meet defined standards. Industry-wide EPDs are available for natural stone cladding, flooring/paving, and countertops. HPDs are available for common natural stone types used in the dimension stone industry including granite, limestone, marble, quartzite, onyx, sandstone, slate, travertine, and more.  (See also: Environmental and Health Product Labels for Natural Stone.)

To further advance these issues, the natural stone industry has been working diligently over the years to make continuous improvements in each area and step of the process. This includes reducing water use, energy use, improving the efficiency of the transportation of natural stone, properly managing and adaptively reusing quarry sites, and many others.

Technology advancements in the natural stone industry have led companies to create zero waste strategies that use every part of a stone block. Photo Credit: Coldspring

Stone wall designs can be quickly and easily fabricated using computer numerically controlled machinery, with any waste being used in stone byproducts. Photo Credit: Stephanie Vierra

The natural stone industry has created a certification system that determines if a quarry or fabricator meets defined sustainability standards in key areas of importance. This makes it easier to find and use natural stones that meet the standard, simplifying the process of choosing the right material that not only looks and performs well, but also has the least amount of impact on the environment. The standard is also accepted within the LBC, further ensuring its use in sustainable building projects. The metrics of the Natural Stone Sustainability Standard can be used to vet stone suppliers even if they have not yet achieved certification.  More information is available via the Natural Stone Institute or NSF International.

Manufacturing Impacts Series: Read More

Sintered surface, also known as ultra-compact surface, is an engineered product that is dense, durable, and resistant to stains, heat, and scratches. The material can be used in many different applications including interior kitchens and bathrooms, and exterior applications such as wall cladding and countertops. This is due to the material’s various thicknesses and durability, and because it has a low porosity and does not fade from UV exposure. The intended design gets printed on the surface but typically does not go all the way through the material. This means that the ends and edges may not have the same color or pattern as the rest of the surface. Sintered surface has an increased risk of chipping due to its denseness and hardness. The edges are especially prone to damage if impacted and can be difficult to repair.

Sintered surface is sometimes marketed as sustainable because it contains natural materials. But as you will see from the manufacturing process described below, the use of an energy intensive manufacturing process gives sintered surface a larger environmental footprint than natural stone.

A sintered stone slab with an interesting texture ready for use as a countertop. Photo Credit: Wikimedia Commons/JonSmith37341.

Manufacturing Sintered Surface vs. Natural Stone

Sintered surfaces are created with several natural materials including kaolin, feldspars, silico-aluminates, and clays, which are first mined out of the ground. The raw materials are then transported to a manufacturing plant, where they must then undergo a complex, energy intensive process that simulates, or mimics, hundreds of years of metamorphic change. To manufacture a sintered surface requires several different stages of processing including grinding, mixing, reacting, stabilizing, separating, and drying. This resulting mixture is then subjected to immense pressure and extreme heat—more than 2,000^o F—to fuse the materials together, all of which requires a lot of energy.

In contrast, natural stone requires only quarrying, fabricating, finishing, and transporting. No additive materials or chemicals are required to create natural stone. Stone is formed naturally by the Earth over time. Several types of natural stone, including marble and gneiss, undergo metamorphoses within the Earth’s crust where extreme pressure and heat transform the deposit from a more porous material to a harder and denser material. This process happens over millions of years in the ground. This means natural stone really is a natural material and has many other attributes, including its durability, recyclability, and wide range of aesthetics. Natural stone can be used in many different indoor and outdoor applications as well and contains no Volatile Organic Compounds (VOCs), meaning it does not emit any harmful gases, making it a healthy material. 

Sustainability Concerns

From an overall sustainability perspective, natural stone has a lower environmental footprint than a sintered surface. This is due to the minimal resources used to quarry, fabricate, finish, and transport natural stone. Each step in the sintered surface manufacturing process requires the use of energy, which contributes to the total GWP. The larger the GWP, the more that a given gas warms the Earth compared to carbon dioxide (CO₂) over the same timeframe.

These characteristics and attributes also make natural stone a great choice when seeking a green building rating certification within the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) or the International Living Future Institute’s Living Building Challenge (LBC). The different manufacturing processes and impacts of building materials are being documented in product labels such as Environmental Product Declarations (EPDs) and Health Product Declarations (HPDs). These labels make it even easier to qualify for points and credits within LEED and other green building rating systems using natural stone. The labels document and quantify environmental information on the life cycle of a product and allow you to make comparisons and informed decisions on materials that fulfill the same function. The product labels are also intended to demonstrate that the health and environmental claims are transparent, accurate, and meet defined standards. Industry-wide EPDs are available for natural stone cladding, flooring/paving, and countertops. HPDs are available for common natural stone types used in the dimension stone industry including granite, limestone, marble, quartzite, onyx, sandstone, slate, travertine, and more.  (See also: Environmental and Health Product Labels for Natural Stone.)

To further advance these issues, the natural stone industry has been working diligently over the years to make continuous improvements in each area and step of the process. This includes reducing water use, energy use, improving the efficiency of the transportation of natural stone, properly managing and adaptively reusing quarry sites, and many others.

An example of a stone fabrication plant recycling and reusing water in the polishing stage, saving thousands of gallons of water annually. Photo Credit: Dennett Tile & Stone

The natural stone industry has created a certification system that determines if a quarry or fabricator meets defined sustainability standards in key areas of importance. This makes it easier to find and use natural stones that meet the standard, simplifying the process of choosing the right material that not only looks and performs well, but also has the least amount of impact on the environment. The standard is also accepted within the LBC, further ensuring its use in sustainable building projects. The metrics of the Natural Stone Sustainability Standard can be used to vet stone suppliers even if they have not yet achieved certification.  More information is available via the Natural Stone Institute or NSF International.

Manufacturing Impacts Series: Read More

Porcelain is a hardwearing material that is suitable for both indoor and outdoor design projects. Porcelain slabs or tile are often used for kitchen and bathroom counters, flooring, stairs, and windowsills. It is a fairly thin material, typically manufactured to be only ½” thick. The basic ingredients that go into the process of manufacturing porcelain are clays, sands, and different feldspar minerals. Because it contains some natural materials, porcelain is often marketed as a sustainable material. Porcelain is also produced to emulate the beauty and veining of marble. But as you will see from the manufacturing process outlined below, the use of many materials and additives and the energy intensive processes involved in its manufacturing create a larger environmental footprint for porcelain than natural stone.

Manufacturing Porcelain vs. Natural Stone

Raw materials like clay, feldspar, and other materials must first be mined out of the ground and then transported to a manufacturing plant. The next step in the process is the intake, storage, and sorting of the required raw materials. Additives such as inks and glazes must also be transported to the manufacturing plant, where they undergo further sorting, mixing, forming, drying, and pressing. Images and glazes are applied to the porcelain surface at this stage. Then, extreme heat is required to fire and glaze the materials into the final porcelain product.

Manufacturing impacts of porcelain.

In contrast, natural stone requires only quarrying, fabricating, finishing, and transporting.  No additional materials or chemicals are required to create natural stone. The Earth naturally forms the material over time.  This means natural stone really is a natural material and has many other attributes, including its durability, recyclability, and wide range of aesthetics. Natural stone can be used in many different indoor and outdoor applications as well and contains no Volatile Organic Compounds (VOCs), meaning it does not emit any harmful gases, making it a healthy material.

Manufacturing impacts of natural stone.

Sustainability Concerns

From an overall sustainability perspective, natural stone has a lower environmental footprint than porcelain due to the minimal resources used to quarry, fabricate, finish, and transport it.  All of the steps in the manufacturing process of porcelain require the use of a lot of water and energy which contribute to the total GWP. The larger the GWP, the more that a given gas warms the Earth compared to CO₂ over that same timeframe.

These characteristics and attributes also make natural stone a great choice when seeking a green building rating certification within the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) or the International Living Future Institute’s Living Building Challenge (LBC). The different manufacturing processes and impacts of building materials are being documented in product labels such as Environmental Product Declarations (EPDs) and Health Product Declarations (HPDs). These labels make it even easier to qualify for points and credits within LEED and other green building rating systems using natural stone. The labels document and quantify environmental information on the life cycle of a product and allow you to make comparisons and informed decisions on materials that fulfill the same function. The product labels are also intended to demonstrate that the health and environmental claims are transparent, accurate, and meet defined standards. Industry-wide EPDs are available for natural stone cladding, flooring/paving, and countertops. HPDs are available for common natural stone types used in the dimension stone industry including granite, limestone, marble, quartzite, onyx, sandstone, slate, travertine, and more.  (See also: Environmental and Health Product Labels for Natural Stone.)

To further advance these issues, the natural stone industry has been working diligently over the years to make continuous improvements in each area and step of the production process. This includes reducing water use, energy use, improving the efficiency of the transportation of natural stone, properly managing and adaptively reusing quarry sites, and many others.

Halibut Point State Park in Massachusetts is a former granite quarry reclaimed into a public park. Photo courtesy of Mass.gov.

The natural stone industry has created a certification system that determines if a quarry or fabricator meets defined sustainability standards in key areas of importance. This makes it easier to find and use natural stones that meet the standard, simplifying the process of choosing the right material that not only looks and performs well, but also has the least amount of impact on the environment. The standard is also accepted within the LBC, further ensuring its use in sustainable building projects.  Even if a natural stone is not yet certified to the standard, the information can be used to vet stone suppliers and ask important questions to help choose the optimal natural stone for your project. More information is available via the Natural Stone Institute or NSF International.

Manufacturing Impacts Series: Read More

There are many building materials to choose from when designing or remodeling a project.  Engineered quartz is one material that is often used in interior projects, especially for countertops. It comes in a variety of colors, patterns, and textures. The product is made by combining natural and manmade materials including quartz, resins, pigments, and other ingredients.  It is a hard, dense, and nonporous material but can only be used on interiors because the resins are not UV stable for outdoor use. Engineered quartz is often manufactured to mimic popular natural stones, especially white marble, but tends to have less variation or veining than natural stone. Engineered quartz is sometimes marketed as a sustainable, natural material because of the quartz in it. However, as the process of manufacturing engineered quartz below demonstrates, that is not the case.

Manufacturing Process for Engineered Quartz

The manufacturing process for engineered quartz includes many energy and resource intensive steps, resulting in a greater impact on the environment. First, quartz is quarried or mined out of the ground, then crushed. Several other additives are required, such as polyesters, resins, acids, alcohols, styrene, peroxide, and other chemicals to create a series of chemical reactions. These additive materials all have to be manufactured and then transported to a manufacturing plant where they will be mixed and put into molds, compacted, and often heated and cured to create slabs. Depending on the manufacturer, the resulting slabs will vary in size, thickness, and appearance. Since engineered quartz is manufactured and installed in slabs, the seams will be visible in a large countertop application. Also, while engineered quartz is manufactured to be somewhat heat resistant, it is not as heat resistant as natural stone. For example, it cannot be used as flooring over radiant heat because of possible damage from the long-term heat exposure.

Manufacturing impacts of engineered quartz.

Sustainability Concerns

Comparatively, natural stone can be used in most applications and requires only quarrying, fabricating, finishing, and transporting. No additional materials or chemicals are required to create natural stone. The Earth naturally forms the material over time. This means natural stone really is a natural material and has many other attributes, including its wide range of aesthetics, durability, and recyclability. Natural stone contains no Volatile Organic Compounds (VOCs), meaning it does not emit any harmful gases, making it a healthy material.

Manufacturing impacts of natural stone.

The materials used and the multi-step process required to manufacture engineered quartz also result in a higher global warming potential, as shown below. From an overall sustainability perspective, natural stone has a lower environmental footprint than engineered quartz due to the minimal resources used to quarry, fabricate, fabricate, finish, and transport it. The impacts of these processes have been documented and systematically compared against other materials using the same environmental criteria. This information is a valuable resource when selecting a sustainable material for a project.

Global Warming Potential

The embodied carbon quantities displayed were estimated based on the following:
Unite of Measure: Global Warming Potential (kg CO₂ eq)
Functional Unit: 1m²
Scope: Raw Material Extraction, Transportation, Manufacturing (A1-A3)
Natural Stone: Industry-Wide EPDs for Cladding, Flooring & Countertops
Pre-Cast Concrete Cladding: Industry-Wide EPD for Architectural Precast Panels, 150 lbs per ft3, 4” thick
Engineered Quartz: Average of three individual manufacturer EPDs
Terrazzo: Average of three individual manufacturer EPDs

These characteristics and attributes also make natural stone a great choice when seeking a green building rating certification within the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) or the International Living Future Institute’s Living Building Challenge (LBC). The different manufacturing processes and impacts of building materials are being documented in product labels such as Environmental Product Declarations (EPDs) and Health Product Declarations (HPDs). These labels make it even easier to qualify for points and credits within LEED and other green building rating systems using natural stone. The labels document and quantify environmental information on the life cycle of a product and allow you to make comparisons and informed decisions on materials that fulfill the same function. The product labels are also intended to demonstrate that the health and environmental claims are transparent, accurate, and meet defined standards. Industry-wide EPDs are available for natural stone cladding, flooring/paving, and countertops. HPDs are available for common natural stone types used in the dimension stone industry including granite, limestone, marble, quartzite, onyx, sandstone, slate, travertine, and more.  (See also: Environmental and Health Product Labels for Natural Stone.)

To further advance these issues, the natural stone industry has been working diligently over the years to make continuous improvements in each area and step of the process. This includes reducing water use, energy use, improving the efficiency of the transportation of natural stone, properly managing and adaptively reusing quarry sites, and many others.

The natural stone industry also created a certification system that determines if a quarry or fabricator meets defined sustainability standards in key areas of importance. This makes it easier to find and use natural stones that meet the standard, simplifying the process of choosing the right material that not only looks and performs well, but also has the least amount of impact on the environment. The standard is also accepted within the LBC, further ensuring its use in sustainable building projects. Even if a natural stone is not yet certified to the standard, the information can be used to vet stone suppliers and ask important questions to help choose the optimal natural stone for your project. For more information, see the Natural Stone Institute’s website at: www.naturalstoneinstitute.org/sustainability.

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