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Siga’s polymers are guaranteed to last for 50 years, which means they’ll continue to ensure air tightness – a key element of passive house.Martin Knowles/Siga

Here’s a rare 2021 supply chain story with a happy ending.

Earlier this fall, the new tenants of a Hamilton, Ont.-based YWCA affordable housing complex for women-led families began moving into their newly completed digs – one-, two- and three-bedroom units, situated in one of the largest “passive house” projects to be completed in Ontario to date.

“Passive house” is an approach to building extremely energy efficient, air-tight dwellings using thick insulation, heat recovery systems, triple glazed windows, with no so-called “thermal bridges” – i.e., places where heat can escape. The YWCA building, says project lead Deborah Byrne, director of passive house design at Kearns Mancini Architects (KMAI), will use about 90 per cent less energy than a comparable structure built to conventional standards.

While some components of passive house projects are specialized, such as windows and HVAC systems, Ms. Byrne says her team had no difficulty sourcing them – a pleasant surprise, given the extreme delays at many construction sites. “There hasn’t been any supply chain issues,” she comments. “We’ve gotten the materials we wanted when we needed it.”

The reasons are worth unpacking: the YWCA had asked Ms. Byrne’s contractors to source locally wherever possible as a point of principle, and those instructions offer a glimpse at the evolution of a growing segment of the building materials sector that is pivoting to supplying low-carbon components to developers and contractors looking to erect low-emission buildings.

The YWCA building in Hamilton will use about 90 per cent less energy than a comparable structure built to conventional standards, says project lead Deborah Byrne.Industryous Photography

In British Columbia, and increasingly in Ontario, progressively tougher regulations in building energy performance – known in B.C. as the “Step Code” and in Toronto as the “Green Standard” – have spurred demand for lower carbon components but also innovation.

“Now that we have [the] step code,” says Sean McStay, vice-president of sales and operations for Siga Swiss Canada, a Swiss manufacturer of highly resilient sealing tapes and membranes, “regular everyday builders that wouldn’t traditionally look at these types of products almost have to look at a higher performance product in order to hit these new building code requirements, depending on which city they’re in. The target market and customer has certainly expanded quite a bit.”

Siga set up a Canadian office and distribution centre six years ago, and has increased its staff from one to 10 in that time. Unlike conventional sealants, which are made from plastics, the company’s products are made of acrylic polymer, a water-based material. Mr. McStay points out that plastics used in building materials give off volatile organic compounds (VOCs), which are associated not only with poor air quality but degradation.

As Ms. Bryne explains, “We have to tape every panel and floor panel [and window] because if we don’t, we have air leaking out through the gaps.” With conventional tapes, she adds, the sticky backing eventually breaks down and loses its grip, allowing heat to escape. Siga’s polymers, by contrast, are guaranteed to last for 50 years, which means they’ll continue to ensure air tightness – a key element of passive house.

While Siga’s tapes cost about twice as much as conventional products, Mr. McStay says these materials account for a small portion of overall construction projects, yet produce a significant savings in terms of ensuring that heat doesn’t escape. “Our part of the construction budget is very small. If you’re looking at a single-family home, some of our competitors are going to be $3,000, depending on the home, and we might be $4,500 or $5,000.”

The YWCA project didn’t just use higher quality materials; it also appears to have driven one Canadian supplier to design a more energy efficient component for the domestic market.

The building, like most new multi-floor apartments, is made of pre-cast concrete slabs, which are essentially designed like sandwiches – two layers of concrete encasing a core of insulation. Typical pre-cast panels have an insulation value of R-20 – or four inches in thickness – but the passive house standard requires double that amount.

Ms. Byrne approached Coreslab Structures (Ontario) and asked if they could upgrade the insulation in their panels for use in the interior walls of the Y project.

The company, which had been looking at designing more energy efficiency panels, came back with a counterproposal, says Joshua Fede, Coreslab’s business development manager. They could do the entire YWCA residence, instead of just the interior walls, and develop high performance panels that would provide the necessary insulation on the whole envelope. “It was our first project with a passive house project, and we kind of had to start from scratch.”

Since taking on the YWCA project, Coreslab has had inquiries from contractors looking for more energy efficient panels.Coreslab Structures

To boost the insulation, Ms. Bryne recommended they use an Irish-made “phenolic foam” product, KoolTherm K20, which goes between the concrete panels and delivers a higher R-value per inch than conventional foam. Consequently, the panels only had to be increased in width by 25 per cent instead of doubled, meaning more interior space and less disruption in Coreslab’s production process, says Mr. Fede. “We didn’t have to reinvent the wheel.” Adds Ms. Byrne: “They just did it; they just bought into it.”

The only other alteration had to do with the clips that hold the panels together. These are traditionally made of steel. But because steel clips, which are highly conductive, produce heat loss, Ms. Bryne asked Coreslab to use fibreglass clips instead.

Mr. Fede says the overall cost of Coreslab’s new passive-house grade panels are about 5- to 10-per cent more than conventional ones. But, he adds, insulation, like sealing tape, is a relatively small portion of overall project cost, so the return on investment is high.

Since taking on the YWCA project in Hamilton, Coreslab has had inquiries from contractors looking for more energy efficient panels, either for passive house-certified buildings or projects designed to meet the standards. “I think the market is going to continue to want to see these kinds of things,” predicts Mr. Fede. “[Developers] know there’s government incentives to help them push towards greater performance. It will be slow but we’ll see organic growth.”

Ms. Bryne adds that KMAI has several more multi-unit passive house projects in the works, in Hamilton, Windsor and Sudbury. The upshot: as in B.C., where increasingly demanding energy codes are translating into green jobs, spurring R&D investment and driving a boom in passive house development projects, suppliers like Siga Swiss and Coreslab are expecting more orders and growing interest in the years to come.

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