When developing a new, roughly 1,500-m2 office building to house its growing staff, Charter Telecom enumerated several priorities: occupant comfort, a high-quality work environment, low operating costs, and of course, reasonable construction costs. Many of the employees have been there for 20 years or more, and their well-being is an ongoing priority. After discussions with Graeme Verhulst of Waymark Architecture, Passive House seemed a good fit for meeting Charter Telecom’s objectives.
The site was a bit narrow—less than 20 metres—and had to accommodate the office plus parking. Raising the building and providing surface parking underneath proved the most cost-effective solution. No columns could interrupt the drive aisle, and zoning setback requirements only allowed enough space for a row of columns on the west side, which couldn’t interrupt access to the parking stalls—a structural challenge, especially for this seismically active area. The shear forces in this configuration were too large for light wood framing, but instead of using high-embodied-energy steel or concrete, engineered mass timber was chosen as the primary structural material.
The design solution that Waymark Architecture arrived at involved creating three masses. A long, skinny block extends the full height of the four-storey building and does most of the seismic heavy lifting, relying on thick, tightly spaced shear walls. The electrical and plumbing services fit within this block, as well as the washrooms, elevator, and fire exits.
The main office space is a two-storey block that spans the structure, providing flexible open offices that can be subdivided with temporary partitions for privacy. A stairway in the middle of this block creates a feature and a connecting element, making possible casual conversations in midtransit; the stairway doubles as bleacher seating for gatherings of 60 or 70 people. The final, smaller mass on the fourth level houses a multipurpose space that will be used for training events and holiday parties, and an executive hospitality suite.
Verhulst notes that an important consideration in moving from design to cost-effective construction was planning the sequencing of the envelope system so that coordination among the trades was optimized. The wood structure—built using cross laminated timber, glulam beams, and sections of light wood framing—was prefabricated off site. Once it was assembled on site, the envelope crew had a flat surface ready for the installation of the air barrier and a Larsen truss stuffed with cellulose. The cladding crew finished off with a mix of fibre-cement and metal siding.
Passive House Metrics
Cooling and dehumidification demand
Primary energy renewable (PER)
Although the climate on Vancouver Island is heating dominated, this building type is dominated by the cooling demand, because of the density of employees and office electronics. To determine the precise loads, the mechanical designers used a dynamic energy model that allowed them to model setpoints, schedules, solar gains, and overheating risk on a zone-by-zone basis. Cooling and heating needs are being met by a variable refrigerant flow heat pump system. To meet specific fresh-air needs in the different spaces, four separate ventilation systems were chosen: two commercial-sized HRVs with one on each of the main office floors, a residential-sized HRV for the hospitality suites, and another one for the main meeting room.