Green Building & Natural Stone
Sustainability Through Natural Stone
A conversation with the Natural Stone Council’s John Mattke
Three years ago, the Natural Stone Council (NSC) took enormous steps to establish natural stone as a preferred, sustainable building material. After the most comprehensive survey to date of the natural stone industry’s practices, the NSC, in partnership with the University of Tennessee’s Center for Clean Products (CCP), has produced a library of information regarding Genuine Stone® and the environment (www.genuinestone.com). Their progressive research has substantiated that natural stone possesses many benefits and is a smart green building material.
NSC Co-Chairman and Chair of the NSC’s Sustainability Committee, John Mattke, recently provided Masonry with an update on the organization’s and industry’s efforts.
John Mattke: The NSC was committed to substantiating the industry’s environmental footprint through scientific means using a credible and neutral third party that we found in CCP. We were sensitive to “greenwashing” and did not want to be associated with it in any way. (Greenwash is a term used to describe the practice of companies disingenuously spinning their products and policies as environmentally friendly.)
Our research enabled us to create baselines from which the stone industry can measure progress and solidify the environmental advantages of utilizing stone products. Through an analysis of the data we collected, we have initiated industry-wide solutions to reduce the life-cycle impacts of stone products by developing a series of best practices to convey how the natural stone industry supports the green movement in quarrying, fabrication and reclamation. We created independent life-cycle inventories of natural stone products that we are currently using to populate a Life Cycle Assessment (LCA). The results of the LCA will feed into material selection and evaluation tools such as Athena Calculator, Pharos, BEES, the Living Building Challenge building material questionnaire and the like. This fall, we also will complete an LCA on stone cladding and various competitive materials.
We have focused on communicating stone’s environmental performance effectively within the industry and the green building marketplace through material fact sheets, data sets, case studies, trade events, etc. If you aren’t aware of the library of resources we’ve established, please visit www.genuinestone.com/env_researchandresults.php.
Mattke: I think all of the resources we’ve produced will be of interest to masons. If forced to pick one, I’d recommend reviewing our transportation best practice, www.genuinestone.com/content/file/Best Practices/Transportation Best Practice 071409.pdf. We found that implementing transportation management promotes shipment efficiency, ultimately minimizing negative impacts to the environment and reducing costs. A comprehensive and proactive transport strategy can also improve carrier-shipper relations and enhance the quarry’s, processing facility’s or mason’s reputation for social responsibility. Masons would also benefit from our case studies (www.genuinestone.com/env_researchandresults.php), which will help them better understand, maintain and execute the designers’/architects’ green design and specification of intent.
Mattke: In a word, “Yes!” Genuine Stone is a natural product that is durable and easy to maintain, and that lasts for more than 100 years. As stated earlier, the NSC has worked hard to ensure that we credibly characterize natural stone ourselves before it was defined by others for us. We have been extremely proactive and engaged a third party to help us, so that we can safely and accurately say that natural stone is green. Now that we have a better understanding of our environmental footprint, we can effectively compare natural stone to other building products and look at where we need to improve.
Mattke: Our overall Life Cycle Assessment will answer this question. In it, researchers evaluate different “Environmental Impact Categories” such as global warming, acidification, eutrophication, habitat alteration, natural-resource depletion, solid-waste generation, ozone depletion and indoor air quality, among other factors. This is the most quantitative and holistic approach to compare the numbers of one product relative to another.
Comparison of natural stone to other products also depends on who the stakeholder is and if they’re seeking some kind of certification like GreenSeal, GreenGuard, EcoLabel, or LEED.
Mattke: There are a variety of ways that stone can currently contribute to LEED points:
SS Credit 7.1: Heat Island Effect, Non-Roof: Using light-colored natural stone with a solar-reflective index of 20 or greater can reduce heat-island effects.
EA Credit 1: Optimize Energy Performance: Natural stone has good thermal mass, which positively impacts indoor ambient air temperature and, thus, energy efficiency.
MR Credits 1.1 & 1.2: Building Reuse, Maintain 75 percent to 95 percent of Existing Walls, Floors, and Roof: These credits apply if the life-cycle of existing building stock can be maintained in a project.
MR Credits 2.1 & 2.2 Construction Waste Management, Divert 50 percent to 75 percent from Disposal: These credits apply if “waste” stone used in construction is diverted to a beneficial use, rather than being disposed.
Credits 3.1 & 3.2 Materials Reuse, 5 percent to 10 percent: These credits apply if salvaged stone products can be reused for another purpose in a building design.
MR Credits 5.1 & 5.2 Regional Materials, 10 percent to 20 percent Extracted, Processed & Manufactured: These credits apply if the project uses natural stone that has been extracted, harvested or recovered, as well as manufactured, within 500 miles of the project site for a minimum of 10 percent (based on cost) of the total materials value (if only a fraction of a product or material is extracted/harvested/recovered and manufactured locally, then only that percentage, by weight, contributes to the regional value).
Products to Watch
QUIKRETE’s Green Concrete Mix consists of a blended concrete mix composed of 50 percent recycled materials, which include recycled aggregates, fly ash (a post-industrial by-product) and/or slag cements. With the use of recycled materials, QUIKRETE Green Concrete Mix diverts material from the waste stream and preserves virgin aggregate resources. As an example, for each 60-pound bag of material, there is about 0.25 cubic feet of waste diverted from the landfill volume.
Suitable for general concrete work, the mix offers a similar set-time and strength characteristics as standard QUIKRETE Concrete Mix. QUIKRETE Green Concrete Mix reaches a compressive strength of 3,500 psi in 28 days and meets the performance requirements of ASTM C 387. The mix also qualifies for points within the Recycled Content and Regional Material classifications as defined through the U.S. Green Building Council’s LEED Green Building certification. QUIKRETE Green Concrete Mix is currently available in northern California and the Pacific Northwest with additional expansion based on market demand and interest.
QUIKRETE’s newest addition is a line of veneer stone mortars, QUIKRETE Natural Stone Veneer Mortar, a contractor-grade mortar mix designed for veneer applications and tuckpointing of natural stone. The mortar can be used as a bond or scratch coat and as mortar joint grout over code-approved substrates, including plywood with metal lath and on other concrete and masonry surfaces. The coverage in joints will vary with width.
The line includes the standard QUIKRETE Veneer Stone Mortar, which can be used in mortar joint applications, as a bonding coat to adhere stone to a wall and as a 3/8- to ?-inch scratch coat over expanded metal lath, and the QUIKRETE Polymer Modified Veneer Stone Mortar for improved mortar to unit compatibility and optimal bond strength. The mortars are available in 80-pound bags and 3,000-pound super sacks. Custom formulations are available including integrally colored blends to meet specific large project requirements.
In anticipation of the development and release of future versions of LEED 2009, a revised point system based on the application of life-cycle assessment to support LEED credits, the NSC relies on the data collected through the benchmarking survey. The resulting life-cycle inventory data sets have been made publicly available on the NSC Web site to make transparent the extent and affect of stone industry operations and to support an informed decision regarding stone products. The datasets can be accessed at www.genuinestone.com/
Beyond LEED, the green building movement has inspired numerous other green building certifications and programs in the United States and abroad. Some of these programs, such as The Living Building Challenge, seek to inspire builders, owners, architects, engineers and design professionals to build environmentally sound and self-sustaining buildings – buildings that actually “give back” to the ecosystem in which they are built. Developed in 2005 by the Cascadia Region Green Building Council, the Living Building Challenge promotes “no credits, only prerequisites,” meaning buildings must meet requirements such as generating all of its own energy with renewable resources, capturing and treating all of its water on site, and using resources efficiently and for maximum beauty. The program is comprised of six performance areas, or “petals,” including site, energy, water, materials, indoor quality, and beauty and inspiration. Each petal includes prerequisites that must be met in order to achieve that specific performance area designation.
Finally, the NSC is coordinating international discourse around the development of a green certification program for natural stone products. The certification is projected to address environmental topics, in addition to social and economic aspects of industry operations. We have been referencing the Forest Stewardship Council’s work on a “Chain of Custody” certification program to inform our thinking. We anticipate sharing more information on this effort in 2010.
Mattke: We hope that they understand and appreciate the stone industry’s overarching goal of positioning stone as not only a green building material, but also the preferable green building material. The NSC would also encourage masons to implement some of the best practices we’ve identified and use green materials.
Mattke: You are already a part of the stone industry community, given the nature of your business. By joining the NSC, you would be on the front lines of the industry’s sustainability effort and be able to leverage an established network of like-minded people. The natural stone industry is building for the future, and we would certainly welcome your involvement.