Editorial: Building Resiliency
The Intergovernmental Panel on Climate Change’s 2022 report focuses on the impacts of climate change, and the capacities of natural and human systems to adapt. Among its findings, it notes how the implementation of low-carbon practices within specific sectors—including buildings—is key to mitigation.
The report highlights strategies such as using more wood in buildings to lower emissions, the wide deployment of green roofs in urban areas to reduce extreme heat, and using passive design strategies for heating, cooling, and ventilation.
But there are also implicit trade-offs: for instance, enhancing space conditioning in buildings can tame the health risks of extreme heat, but comes with a carbon cost. Tightly sealed buildings reduce energy consumption, but may also lead to moisture build-up in envelopes. Increased insulation without shading and ventilation can come with a lowered ability to benefit from nighttime cooling. And while policy changes can be effective, they can exacerbate inequities. “Changes to design standards can scale quickly and widely, but retrofit of existing buildings is expensive, so care must be taken to avoid potential negative impacts on social equity,” write the report’s authors.
Altogether, “building today for resilience and lower emissions is far easier than retrofitting tomorrow,” notes the report. Some $90 trillion USD is expected to be invested in new urban development by 2030. It’s “a global opportunity to place adaption and mitigation directly into urban infrastructure and planning,” write the report’s authors. “If this opportunity is missed, if business-as-usual urbanisation persists, then social and physical vulnerability will be not so easily confronted.”
These issues were top of mind for speakers at the Facades+ conference, which convened in Toronto this summer. While many individual architects and researchers are developing expertise in highly sustainable construction, how do we instigate a change in construction culture, so that higher performance buildings are the norm, rather than the exception? Can we create buildings that radically reduce their reliance on—or entirely eliminate—mechanical heating and cooling? And how do we balance operational energy efficiency with sharp reductions in the embodied energy needed to create buildings?
“We cannot continue with a myopic focus on operational energy, full stop,” said Kelly Alvarez Doran, Senior Director of Performance & Provenance at MASS Design Group. As director of the Ha/f Research Studio at the University of Toronto’s Daniels Faculty, Alvarez Doran has led research on how to halve the embodied carbon emissions of new buildings in Toronto, using currently available materials and technology.
With his students, he has identified key drivers of high embodied carbon in Toronto’s mid-rise residential buildings—including underground parking areas (made with high embodied-carbon concrete) and aluminum extrusion-based glazing systems (the highest embodied global warming potential by volume of all materials in their study). They’ve also done a deep dive into mass timber buildings, revealing substantial upfront and operational emission reductions achieved by reducing window-to-wall ratios and incorporating mass timber into façades.
Considering façade construction, panellist Cathy McMahon, of Moriyama & Teshima Architects, asked: “How can we be growing the things that clad our buildings rather than extracting them from halfway around the world?” Her firm is collaborating with Acton Ostry Architects on Limberlost Place, under construction for George Brown College in Toronto. They’re aiming to achieve both low operational and embodied carbon: the 10-storey building boasts a mass timber structure and was originally designed with terracotta tile cladding (later revised to metal panels due to weight), and has a projected thermal energy demand of 54 kwh/m2/year.
The project team is also geared towards sharing knowledge around the project’s development and design: a three-hour workshop on the afternoon of the conference detailed the technical decisions, construction coordination, and technologies used to design and manufacture Limberlost’s high-performance prefabricated façade system. Its structure, too—a beamless system that achieves nine-metre column-free spans, an optimal depth for daylit classrooms—is a non-proprietary system developed by Fast+Epp. “Anyone in Canada can use this,” said Phil Silverstein of Moriyama & Teshima.
We’ve packed this issue of Canadian Architect with recent research and practices in low-carbon construction that we hope will be useful to your work. To move with the speed needed to address the accelerating climate crisis, we will need to learn from each other—and work together.