From electric excavators to net-zero tiny homes, countless forward-thinking ideas were given air time at Tuesday's Green Building Festival


Held at Toronto’s Marriott CF Eaton Centre, the conference united participants in a common theme: change is needed and necessary as we build homes, offices, and cities for the future. The assortment of speakers from around the globe left guests inspired with their progressive examples of sustainable design. 

Front and centre was the desire to create a cultural shift that will better position the world for the future of sustainable design and construction. This means everything from navigating the complexity of renovating existing buildings and the benefits of tiny houses, to the potential offered by large-scale timber projects in urban centres. 

STOREYS was on the scene to take in the main themes of the day -- here's a look at the highlights.

Maximizing the Use of Existing Buildings 

In her presentation Sustainable urban design: How the built environment industry can transform its practices, Hélène Chartier, Director of Urban Planning and Design at C40, stressed the importance of expanding the use of buildings. “Don’t demolish, transform instead,” said Chartier. She highlighted the Collective for Climate, the first net zero neighbourhood. Here, all buildings are reversible -- a growing trend in design meant to maximize the use of existing buildings. Reversible buildings can be short-term -- for example, using offices for other purposes on the weekends -- or long-term, which involves building offices that can be easily converted to housing in the future and vice versa. Other notable talking points included the importance of 15-minute cities, urbanizing in harmony with nature and people, and the importance of public space, which she calls “the living room of every neighbourhood.”

It’s Time to Decarbonize the Building Site 

The European Association of Electromobility president Espen Hauge explained that it was time to use purchasing power as a tool to promote zero emission vehicles on construction sites. “It’s possible to do everything electric,” he said. The City of Oslo decided in late 2019 to switch from diesel to zero emission construction (ZEMCONS) in all projects carried out by the City itself by 2025. The project portfolio of the Oslo City Agency for Water and Wastewater Services alone includes more than $100M of Zero Emission projects for infrastructure construction and renewal. Getting rid of all combustion engines in excavators and trucks in five years was quite ambitious, said Hauge, but in 2022 Oslo is on track, with electric truck, excavators, and machines now front and centre in infrastructure projects. As Hauge points out, not only are electric building sites better for the environment, they eliminate the disruptive noise typically associated with construction sites. “It’s still high cost, but we see this as becoming a mass market that will bring prices down,” said Hauge. 

Mainstream the Retrofitting of Homes

Eliminating the operating emissions from existing buildings remains a major challenge that will require ingenuity and a new multibillion dollar industry, highlighted Peter Amerongen, Energy Conservation Consultant at ReNü Engineering Inc. Amerongen has been retrofitting homes in Alberta since the 1970s and delivered a progress report on the first large-scale application of the EnergieSprong approach -- a unique program approach to retrofit buildings originally developed in the Netherlands -- to building retrofits in Canada. He demonstrated how this modular, industrialized system can potentially deliver retrofits that are net zero and beyond. “The people who live in the units that have been done already are thrilled. You have to live it to believe it,” said Amerongen, acknowledging some initial pushback at the idea. Not only are the homes more energy efficient, they received upgrades like a skylight in the kitchen and plant shelves on the windows. However, the goal is to alter the home as minimally as possible. “It’s not a magic bullet by any means,” admitted Amerongen. At the end of the day, panelized retrofits work as far as they go, and innovation is required to bring down the cost of the other 60-70% of the work, says Amerongen. 

On the office front, Charles Marshall from Dialog -- who was behind the deep energy retrofit of 25-55 St. Clair -- said that the longer we delay making the proper adjustments, the more of a necessity they will become. "These are not quick payment projects," he said. "They represent deeper investments." He also doesn't sugarcoat the fact that working with existing buildings can be a challenge. "It's messy, difficult, and wild to work with older existing buildings," he says. As important as the technical element to retrofits, these projects have the potential to be scaled to get to net zero at the city scale, and used to rejuvenate neighbourhoods and increase community wellbeing.

Net-Zero Tiny Homes Are the Way of the Future 

A number of speakers at the event highlighted the benefits of tiny homes. Not only do the small, purpose-built dwellings represent an example of sustainable housing on the climate front, they offer a solution to combat Canada’s relentless housing affordability crisis. "I'm not going to claim that tiny homes are the only solution to affordability and sustainability," said Scott Bucking, an Associate Professor at Carleton University in the Department of Civil and Environmental Engineering. But they can certainly help.

Bucking outlined the construction of a tiny home on wheels called the Northern Nomad created by Carlton University students. The net-zero energy (NZE) tiny home was constructed for less than one-fifth the cost of an average Canadian home and the embodied carbon invested in achieving NZE is estimated to be paid back in seven to 12 years. Bucking also discussed other possible purpose-built dwelling spinoffs, including off-grid commercial containers.

We Should Build More Buildings Using Timber 

To close out the conference, Oskar Norelius of White Arkitekter discussed the benefits of building large-scale projects with mass timber -- from environmental benefits, to its quality and potential for swift construction. The architect was behind Sweden’s famous new Sara Kulturhus cultural centre. The stunning 20-storey, 28,000-sq.-km development is designed with a structure of glue and cross laminated timber and is one of the world’s tallest timber-made high-rises. "But it wasn't designed to be a showcase for timber," he said. Rather, the project highlights timber as a sustainable building solution -- and one that can be done within a standard budget, he said. The celebrated climate positive building houses a library, two art galleries, six theatre stages and concert halls, along with a 200-room hotel. "Don't make the building less performative because it's made of timber," said Norelius.

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