The Sugar Cube House: How Prefab and Passive House Can Accelerate Infill Housing
Designing for tomorrow’s housing needs today means finding innovative ways to improve the construction industry’s productivity, which will be essential to addressing the current housing crisis. While prefabrication has long been seen as promising, this solution still has not reached the tipping point for mass adoption. Waymark Architecture’s experience with the Sugar Cube house, a custom-designed single-family Passive House on Vancouver Island, shows that prefabrication’s time may have finally arrived. Combining Passive House with prefabrication enabled us to deliver a resilient, future-proof house in an infill lot with less onsite labor needed in a time of a skilled labor shortage—a win-win-win for the contractor, clients, their neighbors, and the city.
The clients contacted us, because they wanted to downsize from their existing heritage home in Victoria, British Columbia and build a smaller home on the newly subdivided lot in their backyard where a shed used to be. This move would allow them to leave a beautiful, but high-maintenance, heritage house, which was also an energy hog, for a new, low-maintenance home that was a more appropriate size for them as empty-nesters, all while staying in the neighborhood they loved. Another key benefit they were after was predicable energy costs, making their financial retirement planning much easier.
From the beginning Passive House certification was set as the goal, and this intention helped win over the city during the approval process. The city’s councilors and staff recognize that infill housing is key—when it’s built well—to addressing the growing need for housing. By designing to the Passive House standard, the design team ensured that the new home is a high-quality and sustainable building that adds to the neighborhood.
The newly created small lot lent itself to an ideal form for both energy performance and cost: a cube. Aesthetic and practical considerations led to the design team putting a ‘hat’ on top of the cube to be the roof. The interior of the house is relatively open across two stories, with a brightly lit staircase on the south-east corner as its central, eye-catching feature. It is a modest-sized house, but carefully placed windows, an efficient layout, and lots of light coming through the stairwell will make the finished space feel generous. During presentations to the city, the design team was able to clearly communicate how design decisions can help achieve—or not—Passive House requirements.
Prefabrication was the next big choice the clients faced—and for them it was an easy one. The clients realized they did not want to have a site that would be in construction for any longer than was necessary, nor did they want to bear the financial burden of owning both their original home and a home under construction for a long period. Choosing prefabrication as the method of construction meant an overall easier process in which much of the work was done off-site in a controlled environment and then assembled in a few days once the foundation was constructed. Finding a prefabricator that could use its standardized process to work with a customized design was essential to the overall success of this project, and we were fortunate to have found Collective Carpentry. The exact same house could have been built on site, but using prefabricated panels took months off the construction schedule.