Resilient architecture | A climate-proof house

The ice storm drove thousands of Quebecers from their homes for a few days this spring. This new episode of violent weather should encourage us to build houses with a “resilient envelope”, say experts.

By her own admission, Stéphanie Robillard-Sarganis went through “hell” when the ice storm caused a two and a half day power outage in her neighborhood of Saint-Eustache in early April. In just a few hours, the temperature in his house built in 1975 plunged below 10°C.

“We had to sleep under a pile of blankets, with our toque on our heads,” recalls this specialist educator, mother of two elementary-aged children. “We would have liked to take refuge elsewhere, but we had contracted gastro in the family. We had no hot water and the food from the fridge was in the snow. »

This case is not unique. On the morning of April 6, nearly 1.1 million Quebecers were without electricity, which notably prompted the City of Montreal to open eight emergency shelters. This scenario is likely to occur more often in the coming years due to climate change.

Indeed, according to Hydro-Québec, these upheavals will put its network to the test with growing vegetation, forest fires, invasive species and extreme precipitation. These disturbances will also cause increasingly intense heat waves, according to Ouranos.

Without heating or air conditioning

Indeed, Lady Weather does not only strike in winter. Almost every summer, mercury breaks records and claims lives. “In Montreal, the 2018 heat wave caused the death of 65 people,” recalls Dominique Thomas, civil engineering researcher at the University of Sherbrooke (UdeS).

In short, in the event of a power outage, our homes too often turn into coolers in the winter and ovens in the summer.

This is why, plead the specialists, it becomes imperative to build “resilient” houses and buildings, capable of remaining habitable during heat waves or cold winters, without heating or air conditioning.

The key lies in the quality of the insulation and the impeccable sealing of the house, explains Emmanuel Cosgrove, of Écohabitation, an organization dedicated to promoting sustainable construction.

“The temperature in a house with no air leaks, triple glazing and thick walls with an insulation rating of R49 will change only 2°C in three days during a heating or air conditioning failure , he says, supporting studies. The sunshine and the heat released by the occupants will recover the degrees lost during a winter night. »

To illustrate his point, Mr. Cosgrove makes the analogy between a thermos bottle and a filter coffee maker. “The thermos will keep the coffee hot for a long time. The drip coffee maker has to stay on all the time because the heat escapes through the glass of the carafe,” he explains.

A matter of money

This increased efficiency increases construction costs, acknowledges Emmanuel Cosgrove. “But this money will quickly be recovered in operating costs,” he adds. Écohabitation also has a catalog of so-called “passive” kit houses, whose heating costs are reduced to approximately $1,000 per year.

However, consumers are not ready to pay for this quality, laments Montreal entrepreneur Simon Gareau, of the firm Devauban, which specializes in the construction of low-energy plexes. “When I talk about a LEED-certified project, everyone runs off. People need to see. They prefer to put their money on nicer counters than in what’s in the walls,” he points out.

Mortgage financing rules work against high quality construction, noted for his part Patrick Ranger, general manager of the firm Belvedair.

To make the invoice more digestible, the architects of Belvedair looked for where to put the money “where it counts”, says Patrick Ranger. Their solution: triple thermos windows and reduced wall insulation to R33 — still 35% higher than the Novoclimat standard.

“60% of the heat loss in a typical house comes from the windows and 12% from the walls. Triple thermos glazing alone reduces this loss to 40%. For the same dollar, it is therefore more profitable to put the money on quality windows,” explains Mr. Ranger.

Stéphanie Robillard-Sarganis would love to own such a house, she says, “but it won’t be possible with [son] educator’s salary.

Closing the loopholes

So how can you improve the resilience of a bungalow from the 1970s, for example, whose exterior walls were then constructed of simple 2 x 4 studs? Several experts advocate an operation called in English “Deep Energy Retrofit” which consists, roughly, in adding a second insulating envelope outside or inside the house. According to the organization Retrofit Canada, located in Edmonton, such an operation can increase the energy efficiency of a house by 70% and reduce its CO2 emissions.₂ of up to 400 tons per year.

“In an ideal world, it’s the best solution,” says Dominique Derome, from UdeS. But, realistically, few homeowners can invest that much money to refinish their exterior or downsize their interior rooms. »

According to this engineer, a first gain in efficiency can be quickly obtained by better insulation of the roof, by quality windows, but above all by hunting for leaks. “Buildings dating from before 1990 are not very airtight. Faults can easily be found by performing a leak test. By sealing the holes around windows and walls, you get better comfort immediately. »

Isabelle Thomas, director of the research group AriAction, suggests for her part that Quebec establish a program for owners wishing to improve the resilience of their home, in particular to avoid “eco-gentrification”. “It’s obvious that we have to support them, with technical and financial assistance, in this process,” says the professor from the Université de Montréal.