Construction company Butterwick Projects Ltd. has completed a “deep panelized retrofit” for a single-family home in Edmonton — the first of its kind in North America.
For this home and two others, Butterwick partnered with open-source, non-profit organization Retrofit Canada. The groups were inspired by Energiesprong, a program created by the Dutch government in 2010 to retrofit buildings to net-zero energy primarily using prefabricated panels for increased thermal efficiency.
“There are eight million single-family houses in Canada and they have a lot bigger GHG impact than multifamily, right from the get-go. We realized we needed to very quickly adapt this system to single-family houses and we applied for and got a grant from SSRIA (Smart Sustainable Resilient Infrastructure Association) to do three single-family houses,” said Peter Amerongen, Retrofit Canada treasurer and Butterwick managing partner.
“We went looking for people who wanted to be willing victims, and Jim (Sandercock) was one of them.”
Sandercock, also the chair of the Northern Alberta Institute of Technology’s (NAIT) Alternative Energy Program, and his partner Melanie Harmsma wanted to improve on the energy usage of the two-storey house in the city’s Highlands neighbourhood without tearing down the foundations.
They had already installed solar panels that generate 7.4 kilowatts of power, which is more than the residence needs. But the family still wanted to provide an example of a net-zero-ready home.
The airtight panels were designed using 3D digital imaging and were attached to the exterior walls and roof in less than a day using a spider crane. The rest of the retrofits for the house — originally built in 1951 — will be completed in the next few months, at which point it will use 70 to 80 per cent less energy.
At the time of the interview with SustainableBiz, Bushwick was also constructing the first multifamily home panelized deep retrofit in North America — the Sundance Housing Co-op, 59 wood frame units in Edmonton’s river valley constructed in 1978.
The deep retrofit panelling
Butterwick was founded in 2018 and services net-zero energy, Passive House and deep energy retrofit building projects in Alberta for the multifamily residential, commercial and institutional building sectors.
Retrofit Canada and Butterwick enlisted software developer Logan Gilmour to capture the dimensions of the 1,950 square foot home using drone photography and custom photogrammetry software. Photogrammetry is the practice of measuring and modelling buildings in three dimensions based on photos.
The photos were taken in 2021, with work commencing on Sandercock’s home in May. The panels were installed in mid-June. An explainer video states Gilmour’s photogrammetry process has a 3.5 millimetre accuracy.
According to Amerongen, the originators of Energiesprong in the Netherlands typically use a LiDAR (light detection and ranging) scan.
The two-by-four panels are created with a cavity about eight inches thick, which is then filled with cellulose.
As Amerongen explained, the Bushwick team used LiDAR for most of the Sundance Co-op modelling, which resulted in more mistakes with physical measurements. Using photogrammetry for Sandercock’s home and the two others, the team avoided those errors.
“Really what Peter and the Butterwick team are doing, is doing knowledge transfer from one continent to another, and then perfecting that system or perfecting that method,” Sandercock said.
Retrofit Canada first became aware of Energiesprong in 2016 when three bachelor of technology students partnered with Amerongen for a capstone project. This led to an initial Energiesprong-inspired approach to two Sundance units.
That’s where Sandercock and Harmsma caught wind of the project and signed on.
Aside from the prefabricated panels, an Energiesprong retrofit can also include insulated rooftops with solar panels, smart heating, ventilation and cooling installations.
It is also utilized in the U.K., Germany, France, Italy, with Energiesprong-inspired projects also present in California and New York.
Amerongen and Sandercock were both satisfied with the Energiesprong panelling, and could see uses for it even beyond other single-family homes.
“We think it has potential . . . Different houses are going to have different optimal solution sets,” Amerongen said. “But there’s a subset of houses where I’m convinced it makes sense, and that we can go from projects like this and make it streamlined and make it faster, more industrialized.”
Sandercock noted one of the reasons his family signed on was in the hopes of evolving the Energiesprong-inspired process toward something industrial and scalable.
“We still will have a hard time getting there,” he remarked.