Forward-thinking building designers are taking weather seriously these days. Changing weather patterns can wreak havoc on buildings.
Keeping today’s multi-unit residential buildings cool in tomorrow’s heat waves will be challenging, according to energy modelling studies.
Flooding is another concern and the risk of power failures is increasing as the number of intense storms grows.
Michelle Xuereb, an architect and sustainability strategist at Toronto-based Quadrangle, says through TransformTO, a collaborative project to reduce greenhouse gas emissions by 80 per cent by 2050, the City of Toronto is examining risks associated with weather change through mitigation, reducing the carbon footprint and adaptation, designing and building for weather changes.
While there are no easy solutions, Xuereb says buildings should be designed to be resilient, meaning they can "withstand and recover quickly after an extreme event or remain useable for three to five days" without power, fuel and water.
To meet that end, a multi-residential building’s essential services should be installed above potential flood lines while the building envelope should be tailored to maintain livable temperatures inside.
"In my mind, the best architectural solutions are passive ones," adds Xuereb, whose role at Quadrangle is to keep current with environmental issues, ranging from new materials and technology to government incentives and policy changes.
Research through energy modelling exercises of buildings "unplugged" shows that a well-insulated building envelope with "a reasonable amount of windows" can be resilient to extreme weather for several days, whereas glass-clad buildings with low thermal values can see extreme temperature swings inside within a day, says Xuereb.
The architect explains building envelope performance needs to be "embedded into building codes" independently of mechanical systems. Currently, tradeoffs allow developers to prioritize energy efficiency through mechanical systems. Regulators are exploring alternatives.
She says a "good target" is to set a 40 per cent maximum window coverage in a rainscreen wall system with "high thermal value."
This isn’t new design thinking but rather "passive old-school principles that continue to remain valid."
Xuereb adds while window-wall systems are less energy efficient than curtainwalls or masonry walls with "punched windows," they are common on highrise housing because they are the least expensive option.
"With all the pressures and the pricing in the industry right now, especially with all the work in the city (Toronto), if a developer can pick and choose one product to meet their objectives, I understand the attraction of something quicker and simpler to put up," she says.
To see a change on the building envelope front, Xuereb says the city needs to "mandate the level of performance" and ensure it is enforced.
She says the City of Toronto is looking at changing the way energy metrics of a building are reported to meet Toronto Green Standards in order to improve performance. An objective is to "change from reporting building energy performance in terms of percentage better than the Ontario Building Code to reporting in absolute performance targets," she says.
Similar to the current practice, incentives would be offered for developers meeting higher energy performance standards.
Along with a building’s resiliency in a weather event, "the resilience of a community is what will help people manage these extreme events and recover quickly," she says.
To meet that end, buildings should be designed as places where residents can draw support from each other through power failures.
For example, designing shared spaces in a highrise that allow for "sub-neighbourhoods" is integral to community building, Xuereb suggests, adding designs that improve a community’s resiliency will be a mandate of the chief resiliency office at the City of Toronto.
Developers will get on board if they see the value in something. Even small projects that help to define an area as a neighbourhood can go a long way in affecting change in the built environment, she says.
Xuereb, a speaker at the Green Building Festival 2017 has served on the board of directors for the Toronto chapter of the Canada Green Building Council and is currently on the board for Sustainable Buildings Canada.
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