By: Green Building & Sustainable Strategies
In November 2015, countries from around the world came together with the united goal of solidifying global efforts to reduce the threat of climate change. For the first time, countries made strong commitments to identifying areas in which they would strive for improvement and agreed to specific targets they hoped to achieve. In many countries, explicit carbon reduction strategies will be put into place. In others, a greater effort will be placed on the energy performance of buildings.
Already, most of the countries in the European Union have very high energy performance requirements for buildings, more than 50 jurisdictions – local, regional, and state level – have building codes which specify performance to meet or surpass passive house standard levels.
Canada has distinguished itself as a world leader in high performance design, with more certified green building space per capita than any other country in the world (CaGBC, 2015). As well, Canada’s strong environmental ethic is not driven solely by energy costs, as is the case in other countries.
Around the world, the green building phenomenon of the past has become a mainstream movement to address a plethora of environmental and health concerns of today. Greater attention is being paid to the impacts of the materials that go into our buildings. Are they procured from a sustainable source? Is the manufacturing process as benign as possible? How much energy is used?
In Canada, all levels of government are examining how best to raise the environmental performance of buildings by reducing energy consumption and carbon impacts, enhancing the indoor environment and achieving this in a cost-effective manner.
Wood, a natural material, plays a significant role in a number of these burgeoning areas of concern. It is renewable, organic, non-toxic, sequesters carbon, uses little energy to process and, with the advent of innovative engineered wood products, can replace other materials that have a greater environmental impact.
In addition, new design practices and construction techniques are raising the performance expectations and capabilities of buildings. Passive design, which targets improved air quality and comfort, as well as energy savings of about 90 per cent over conventional code minimum construction, is growing rapidly in Canada; resulting in lowered operational energy use for these buildings. The choice of building products also contributes to lowering the operational impact of a building; as seen with wood’s exceptional thermal resistance properties. Choosing wood components as part of the building envelope, over other more thermally conductive materials, makes it easier to meet design requirements for high performance buildings.
The 2007 Intergovernmental Panel on Climate Change (IPCC) report galvanized countries around the world to undertake the mammoth task of both reducing and mitigating future climate change.
Diana Ürge-Vorsatz, Director of the Center for Climate Change and Sustainable Energy Policy (3CSEP) at the Central European University, was a member of that Intergovernmental Panel on Climate Change. In her keynote address to delegates at the North American Passive House Network, Vancouver, B.C., October 1st, 2015 she said:
“The best way for the planet to reduce its energy use is to build and retrofit every building to a passive design. Compared to all other options, doing so is the fastest, most effective and least expensive way to reduce energy.”
Wood can contribute to energy reduction in several ways.
Firstly, wood is a natural, renewable material grown using the energy from the sun. No fossil fuels are required to grow forests, which absorb carbon dioxide and sequester atmospheric carbon into wood. Forests also act as a huge carbon sink, storing carbon in the forest soils and vegetation.
Wood’s cellular and porous structure also grant it a natural thermal resistance, acting as an effective way to resist heat transfer through walls and floors.
Finally, only wood can cost-effectively be machined to the exact tolerances needed to fabricate the precise components and assemblies critical to the airtightness of ultra-high performing buildings. In addition, as more buildings move to modular construction or significant off-site assembly and prefabrication practices, wood’s low mass means a lower energy and carbon impact due to transportation.
As the world moves towards higher expectations and regulations for building performance, design and construction practices will need to change accordingly. Off-site, prefabricated construction of high-performing buildings, common in Europe, will become the norm in Canada. The concentration of skills and trades in a controlled environment have demonstrated that speed and accuracy are improved along with worker comfort, safety and productivity.
Building codes across the country are gradually changing to acknowledge the performance capabilities of wood products. And still, more change is needed – as many building types that could be constructed safely using wood products are currently not permitted. The recent change in the 2015 National Building Code to allow mixed use mid-rise wood-frame buildings is moving steadily but not yet fully accepted across the country. More complex structures such as taller wood buildings are still not recognized in the code, but possible via an alternative solution. Regardless of the code barriers currently present for tall wood buildings, examples such as the University of British Columbia’s Brock Commons project (an 18-storey wood building), demonstrate the desire from Canada’s design community to elevate building innovation within our country, recognizing the many ecological benefits of wood for taller applications.
Performance-based codes, equal recognition of materials based on true capabilities coupled with greater knowledge by both designers and contractors are all necessary elements to have comprehensive, safe and effective use of wood products in our built environment.
But will an increase in wood use deplete our forests?
Not at all. More than 90 per cent of Canada’s forestland is owned and controlled by government. Maximum harvest levels are set based on the productivity of the forest and the biological limitations and requirements of the land. Canada also has the strictest forest management legislation of any jurisdiction in the world. Our vast, productive forests act as an important carbon sink for the planet while our high level of management ensures there will be a sustainable supply of wood for future generations. Wood, forests and green design are all exquisitely linked in this regard. In fact, when examining climate change mitigation strategies, forests and wood afforded one of the best opportunities to reduce carbon in the atmosphere.
Building with wood, where possible, not only stores carbon but avoids the emissions that would have been caused had other more greenhouse gas intensive materials been used. However, we can and should strive to achieve more from our buildings. Greater emphasis needs to be made on both the performance levels of our built environment and the choices being made for materials to build our structures. Wood can and should play a leading role.
It’s a natural choice – for our well-being, for our economy and for our environment.