Carving viability for natural stone in Canada

September 18, 2017

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Photo courtesy PICCO Engineering

By Michael Salerno
In the design/construction industry, there is a continued search for cladding materials that are reliable, durable, unique, practical, and also environmentally friendly. These requirements can make it difficult to also provide esthetic appeal. Natural stone, however, possesses all of these characteristics and more.

Whether quarried or custom-fabricated, natural stone is a product that has withstood the test of time, and is known for its longevity and grandeur. It can easily be custom-fabricated, and is ‘green’ as well. Despite its age, the stone industry itself is progressive, operating within an environment of continuous improvement. Industry associations such as MIA+BSI: The Natural Stone Institute provide exceptional support. Altogether, natural stone is a safe, practical, and esthetically appealing selection, especially when compared with nouveau, fad-like building materials.

Natural stone’s environmental benefits
During the concept and design phases of a project, natural stone can meet a variety of criteria. Unlike many manufactured cladding materials, which require large amounts of energy to produce, natural stone can be extracted from the earth, processed, slabbed, finished, and cut with great efficiency. As more emphasis is placed on green building programs like the Leadership in Energy and Environmental Design (LEED) rating system, or whole-building design and life cycle assessment (LCA), the concept of ‘embodied energy’ is becoming an important and relevant factor in gauging a material’s viability.

Embodied energy is a measure of the carbon dioxide (CO2) emitted through total energy expended from the material’s extraction to the time it is installed on the building (also known as the time from ‘cradle to gate’). As building designs incorporate more materials—and, specifically, more carbon-intensive materials—to achieve lower energy use, an increasing proportion of carbon emissions from high-performance buildings is coming from those materials and products. By taking embodied energy into account, professionals can ensure they are designing for net carbon emission reductions. In the case of natural stone, this embodied energy could include the CO2 required during quarrying and transportation, as well as the energy required for slabbing and fabrication, site delivery, and installation.

Natural stone is consistently rated as one of the building materials with the lowest embodied energy, according to a study conducted by SISTech in collaboration with Heriot-Watt University. (A report on this study, titled “Embodied Carbon in Natural Building Stone in Scotland,” was written by Naeeda Crishna, Dr. Suzy Goodsir, Professor Phil Banfill, and Dr. Keith Baker, and can be obtained by e-mailing info@sistech.co.uk[2].) It is highly durable, recyclable, low-maintenance, and emits no volatile organic compounds (VOCs). Various organizations in the stone industry have implemented standards and measures to ensure production sustainability, which is also driven throughout the supply chain. Given its widespread availability, comparatively low cost, and reduced environmental impact, stone is expected to play an increasing role in construction.

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This diagram demonstrates the potential yield available from a quarried block and a plan to utilize all extracted material.
Image courtesy Coldspring

Circumventing the challenges of natural stone
Although beauty is in the eye of the beholder, it is difficult to deny the timelessness of natural stone. Its strength and its sustainability are showcased in buildings throughout the world. Additionally, with the sophisticated technology now available to quarries and fabricators—such as computer numerical control (CNC) machinery and robotics—natural stone can also be used for even the most intricate of architectural details.

So, why are there not more stone projects in Canada? Money and time are two key factors in any purchase, and likely play a part here. However, natural stone is neither as costly nor as difficult to use as one might perceive.

It has become something of an industry standard to engage specific consultants such as lighting and sound experts and structural, mechanical, and electrical engineers in the beginning phases of a project. However, specific stone consultants—not to be confused with general façade consultants—are rarely brought onto project teams from the outset.

Stone can be an intimidating material to work with because of its variability. Too often, using stone is dismissed as an option because of a previous experience where problems were caused by the team unknowingly using incorrect stone for the application. Some professionals may have heard of cladding projects going awry because of ‘faulty stone.’ A stone consultant well-versed in façade systems can bring significant value to a project by ensuring the correct stone is used, the proper stone thickness is dictated, and the backup and anchor systems are precisely engineered.

Similarly, a façade consultant possessing specific stone expertise will establish specifications to facilitate an apples-to-apples installation bidding process. Factors such as stone thickness and engineering will be settled upfront, eliminating any need for guesswork by the bidders. Moreover, shop drawings can be created by the stone consultant, with an eye on architectural vision and logistical efficiencies onsite.

Stone consultants can help eliminate excess installation costs and logistical complications, and ensure appropriate material estimating data is used so as to avoid overages or underages. These aspects alone will reap a strong return on investment (ROI). The stone consultant’s role as a custodian of design who can ensure the correct stone for the design is obtained (i.e. stone with the appropriate sourcing, properties, thickness, and fabrication) also facilitates great savings on money and time. The earlier an expert stone consultant is engaged on a project, the more value can be achieved.

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A sample life cycle assessment (LCA) of cladding materials conducted by the Centre for Clean Products as part of the research behind the development of NSC 373, Natural Dimension Stone Standard. This study offers a comparative view of several environmental impact categories and materials, including aluminum, brick, granite, limestone, and precast concrete.
Image © Centre for Clean Products

Case studies
Comparatively speaking, the Canadian market has far fewer stone projects than the United States due to reasons such as quarry locations, proximity, and transportation methods. This being said, some magnificent projects have been completed in the country as of late.

Aga Khan Museum and Ismaili Centre
Toronto’s Aga Khan Museum and Ismaili Centre comprise almost 9290 m2 (100,000 sf) of exterior stone, including cladding and architectural stone elements. Spread across a campus-like environment of 7 ha (17 acres), these elements are not only a feast for the eyes, but also a good example of what a stone consultant can bring to a project.

During the design phase of this project, stone selection was critical. Over 15 months, numerous tests were performed to determine what stone properties were appropriate for the various applications. A careful balance between esthetics and practicality was important. Factors such as climate, pollution from a local highway, quarry options, and potential fabricators were also considered before final decisions. The museum’s design features were executed with the help of detailed shop drawings, as well as precise engineering and anchor system design. Thus, services provided by the stone consultant were vital to this project’s success.

Canadian Museum of Human Rights
The Canadian Museum of Human Rights (CMHR) in Winnipeg is another example of a stone project requiring specific stone expertise. (For more on this project, see the article, “Canadian Museum for Human Rights: Design Excellence and Structural Innovation at the Forks,” by Neb Erakovic, Crispin Howes, and Terry Dawson in the May 2014 issue of Construction Canada. Visit www.constructioncanada.net/canadian-museum-for-human-rights-design-excellence-and-structural-innovation-at-the-forks[5].) Construction manager PCL and architect Antoine Predock both realized consulting a stone expert was imperative early in the project’s development, as stone was one of the key elements in the architectural design from both an exterior and interior perspective.

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This graph depicts the embodied carbon in various building materials, as reported by the Stone Federation Great Britain, in a study that was conducted by SISTech in collaboration with Heriot-Watt University.
Image © Stone Federation Great Britain

The project included a design-assist package clearly outlining the experience and other requirements needed to assist the team of stakeholders. The consultant’s engagement involved investigation of several stone options and visits to the quarry to facilitate understanding of material properties, fabrication capabilities, and limitations. Regular collaboration, including the creation of several mockups, began during the construction document phase to ensure the design intent was being met.

As the project evolved, development of shop drawings and co-ordination with other key stakeholders and contractors—including building maintenance staff—was enacted by the stone consultant. Ultimately, this project’s exemplification of innovative stone design is thanks to the team of stone consultants that influenced and supported key decisions. Predock refers to this project as his favourite, which is quite the statement from an American Institute of Architecture (AIA) Gold Medal award-winner.

Montréal Museum of Fine Arts
Another example of effective collaboration between architect and stone consultant can be seen in the Montréal Museum of Fine Arts. The underlying challenge was modernizing stone from connecting century-old buildings. The result was an eye-catching modern façade mimicking the quarry walls from which the stone was extracted. Effective execution of this goal started with the selection of a stone consultant, whose engagement during the design phase helped facilitate the architect’s vision. This accomplishment would not have occurred without the use of clear and effective shop drawings, a numbering system, and tracking of quarried blocks and slabs.

Conclusion
In all three of the aforementioned projects, project teams and their stakeholders benefitted from the engagement of an experienced stone consultant utilizing advanced technology such as building information modelling (BIM) to streamline the design and construction process. Complex geometric calculations and challenges were met with confidence, and stone applications successfully pushed to the limit in the design stage. However, no amount of technology can substitute expert knowledge of various stone properties and all they entail.

Elaborate claddings are not the only stone assemblies that justify engaging a qualified consultant. It is always best to check with a stone expert when designing with this material, regardless of the project size and scope. Despite stone’s reputation as a difficult building material with a high-maintenance installation process, it is a valuable, easy-to-use resource capable of saving building professionals money and time.

When stone is utilized appropriately and efficiently, the performance it offers and statement it makes are undeniable.

Michael Salerno is responsible for sales, marketing, and business development activities at PICCO Engineering, and is also part of their senior management team. He holds a degree from the University of Toronto, and is heavily involved in the Building Industry Land Development Association (BILD) on behalf of PICCO. Salerno can be reached at msalerno@picco-engineering.com[7].

Endnotes:
  1. [Image]: https://www.constructioncanada.net/wp-content/uploads/2017/09/Photo-G-Aga-Khan-Museum-Front-Facade-with-Reflecting-Pool-e1505761116622.jpg
  2. info@sistech.co.uk: mailto:info@sistech.co.uk
  3. [Image]: https://www.constructioncanada.net/wp-content/uploads/2017/09/Block-photo.jpg
  4. [Image]: https://www.constructioncanada.net/wp-content/uploads/2017/09/LCA-chart.jpg
  5. www.constructioncanada.net/canadian-museum-for-human-rights-design-excellence-and-structural-innovation-at-the-forks: http://www.constructioncanada.net/canadian-museum-for-human-rights-design-excellence-and-structural-innovation-at-the-forks
  6. [Image]: https://www.constructioncanada.net/wp-content/uploads/2017/09/Embodied-Carbon.jpg
  7. msalerno@picco-engineering.com: mailto:msalerno@picco-engineering.com

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