Vancouver-based construction company B Collective specializes in wood-frame panelization, a process that uses factory-built flat panels which can be assembled into houses on location, says company president Chris Hill.Ethan Cairns
Innovative residential construction practices such as off-site factory building and on-site 3D printing are making inroads in Canada’s massive home-building sector.
While they represent a small percentage of overall builds, which are still dominated by traditional stick-framework, these sustainability-focused techniques can add speed and labour-force efficiencies.
Vancouver-based off-site construction management firm B Collective specializes in wood-frame panelization, a process that uses factory-built flat panels, which are assembled into houses on location, says company president Chris Hill. Panelization allows the use of a variety of materials, including dense-pack cellulose, a recycled paper fibre that is naturally carbon-storing, Mr. Hill says. Building walls off-site also improves quality control to ensure greater airtightness and waste reduction, he adds.
B Collective has been involved in projects designed to meet Passive House requirements, a set of building standards aimed at reducing the need for heating and cooling energy. Passive House construction is typically thermal bridge-free (no design elements transfer heat and cold from the outdoors), and it makes use of energy-efficient windows and walls, airtightness, and good ventilation.
“If we were going to do a Passive House today, we would only do it through panelization because our wall systems are designed with airtightness in mind,” Mr. Hill says. “We can build walls at any thickness to meet the R-value requirements of a Passive House.” (R-value is the measurement of how well a construction material resists the flow of heat into or out of a building.)
The first Passive House is going to cost the builder more because you pay to learn. [With] the second or third, the price keeps going down.
— Jeff Clarke-Janzen, project manager, PassiveHouse Canada
Mr. Hill’s firm is still a small operation, with six or seven projects under its belt and another handful under way. There are larger panelization firms across Canada, but it’s still only 2 per cent or 3 per cent of the overall residential construction market, Mr. Hill says.
Critics argue that novel technologies cost more in a market already straining to keep house prices down. But Mr. Hill predicts that factory builds will gain traction, given labour efficiency and faster construction times. “Our productivity in construction is so low we’re being forced to explore different ways to build,” he says.
Speedy construction pairs with structural longevity in 3D-printing construction, another innovation that is relatively new to Canadian residential job sites. Nidus 3D, based in the Kingston area, has been using 3D printing to construct residential buildings for three-and-a-half years.
“We tried to push the envelope where we could, in terms of the type of structures we could put up,” says Ted Urbancic, vice-president of business development for Nidus 3D.
The technology allows workers with 3D-design software to direct a huge on-site 3D-printing machine. The 3D printer combines concrete, sand and other materials to print 3D structures using a robotic arm, or nozzle, to pour layer after layer of material, according to the design specifications.
The firm has printed 25 residential units of various sizes, including its most recent project for an Indigenous group consisting of four buildings with four residential units in each building, Mr. Urbancic says. The buildings are printed on site, with the printer laying down layer after layer of concrete. Mr. Urbancic says that while the first building took about 10 days to print, by the fourth building the process had been reduced to three-and-a-half days.
On the sustainability front, Mr. Urbancic says concrete structures can be built to R-40 standards, well above building-code standards. The longevity of the homes, designed to last for decades longer than conventional builds, also reduces carbon footprints.
B Collective’s Chris Hill says the company has been involved in projects designed to meet Passive House requirements, a set of building standards aimed at reducing the need for heating and cooling energy.Ethan Cairns
Concrete construction plays into the need for climate adaptability, with its resistance to flood and fire damage, he adds. Nidus 3D is currently researching potential building materials beyond conventional concrete to further reduce carbon footprints.
Kevin Lee, chief executive officer of the Canadian Homebuilders’ Association, says there are competing challenges in home building right now – for example, the cost of construction is escalating rapidly, the housing shortage demands faster building in a time of labour shortages, and increased energy efficiency and climate adaptation are being added to building codes.
Factory builds, such as panelization and modular building, shine in terms of labour productivity, Mr. Lee says. His association released a strategy paper last year on how to move toward more factory-built housing.
The upfront cost of building and equipping factories is a barrier to the technology, he adds, but savings can be made during the construction phase. “It’s substantially faster. Panelized is faster. Modular is even faster than that because you can be doing your site prep at the same time as you’re building the entire home.”
Modular construction involves factory builds of entire homes, when they are small, or portions of homes, which can be stitched together on-site, he explains – “you crane the (modules) into place, connect the units, seal the joints, connect the electrical and plumbing.”
Cost is not the only factor that has slowed the rollout of innovative building technologies. It takes time to shift the focus of a huge construction sector that has used the same wood-frame techniques for decades. For instance, builders have been reticent to replace traditional foundation construction with insulated concrete forms, a convenient system for high-performance wall assembly, says Jeff Clarke-Janzen, project manager for PassiveHouse Canada, a non-profit organization that provides support and technical services for builders that are working to achieve Passive House certification.
He says the process costs more, and builders using it for the first time may require expert help with installation. “Once you learn about the system [and] are able to install it yourself, you realize with the proper design … you don’t have to do an interior framed wall. The more you know and the more you play, the cheaper it gets.”
That pattern extends to the wider requirements and techniques for creating a Passive House.
“The first Passive House is going to cost the builder more because you pay to learn. [With] the second or third, the price keeps going down,” Mr. Clarke-Janzen says.
He adds there is increasing demand from builders interested in sustainable construction.
“It’s going to shoot up as more cities catch on and incentivize good buildings, whether it’s Passive House or net zero.”