The Clayton Community Centre will unite under one roof many of the community’s previously separate services, including the library, visual and performing arts, and recreation. It also physically occupies a prominent site for the Surrey neighbourhood of Clayton Heights, much loved for the forested trails it offers. So the centre’s design was a focal point for community input and a major initiative for the city. Setting a high standard for the building in terms of both aesthetics and sustainability, the city approached HCMA Architecture + Design, asking it to design a building that not only would meet the Passive House standard but would do so beautifully. The 7,000-m2 centre demonstrates that environmental performance and high design are very compatible partners.
In its initial design concept, HCMA was expressing its synthesis of the neighbourhood’s values. Community input had reported a strong appreciation for the surrounding forest and a fear that rapid development would deprive the community of this easy connection to the trees. The centre’s atrium pays homage to a forest canopy, with its ceiling of honeycombed exposed glulam beams suffused by dappled light. The glulam structure wraps down the exterior walls, creating openings that angle across the building, much as branches slant across a forest. The extensive glazing in both the roof and the walls—much of which is triangular—maintains the centre’s connection to the nearby still-thriving forest. Exterior insulation is superimposed on the glulam structure, creating a classic Passive House thermal envelope.
Inside, the mix of uses extends the interconnected ecosystem feel and invites cross-fertilization among patrons. Music studios, recording studios, and a community rehearsal hall branch off from social spaces that also afford access to a library, a gymnasium, and a fitness centre. These key services are supported by a unique mix of supplementary uses, imagined and developed in close engagement with the community and designed to allow for community-led programming to occur. These include a community kitchen and associated community garden, a tool-sharing centre with a community workshop, a café, and various preschool and child care rooms.
Early in the design process, HCMA came to realize that Passive House objectives would be a significant driver of the building’s form and layout. For each space, occupancy patterns and anticipated equipment loads were estimated, to help the team to develop a rough PHPP model. Several of these areas—including the community workshop, kitchen, and fitness centre—had atypically high energy loads and internal heat loads. Lighting loads, especially for the double-height spaces, were also exceptionally high. The team realized that the biggest challenges for this building would be minimizing the cooling loads—not heating, as had been anticipated—and meeting the overall primary energy requirement.
The centre is expected to operate from 6 am until 11 pm daily, with an average of more than 650 people per hour using the facility. This intense usage inevitably produces high internal heat gains, pushing up cooling loads. To reduce these loads, HCMA re-evaluated the thick building insulation layer typically prescribed for Passive House projects. Lowering the R-value of the opaque envelope to roughly 22 reduced the cooling loads, but not enough. The addition of a passive ventilation system combined with strategic solar shading brought the cooling loads into conformance with Passive House requirements.
The mild climate in southern British Columbia means that civic and commercial buildings can often benefit from controlled passive ventilation—opening windows when conditions are favourable—even on the coldest days. Different combinations of windows were modelled using specialized natural ventilation software, and their impact on thermal comfort and energy reduction was evaluated. “Finding operable triangular windows that were Passive House certified was a challenge,” says HCMA principal Melissa Higgs. The window manufacturer was very collaborative. “We discussed our design needs, and they came up with solutions,” says project architect Aiden Callison.
Two of the areas that benefited greatly from operable windows were the library and the fitness room, which was moved to the centre’s north side to reduce solar gain and minimize potential overheating. Both spaces have windows at occupant level and high-level clerestory windows. The elevation difference between these openings drives air infiltration. On peak days, occupant comfort will still rely on the mechanical cooling system, but the considerably fewer hours that the mechanical system will be required results in significant energy savings.
The simplicity of the building form, which is at heart two stacked boxes, meant that external shading was not only helping to control solar gain but also adding expression to the building. The upper level provides more than 2 meters of overhang for the lower level. Shading for the upper level is supplied by articulated fins that are 0.15 to 0.5 metres deep and are attached to the curtain wall by a thermal break system so as to not reduce the frame’s performance.
Passive House Metrics
Cooling and dehumidification demand
Primary Energy Renewable (PER)
0.6 ACH₅₀ (design)
With so many people expected to be coming to and going from the facility, figuring out a workable entranceway that wouldn’t result in excessive uncontrolled infiltration was another big challenge for HCMA. Traditional double-door vestibules have been found to be ineffective, because under heavy usage both sets of doors often open simultaneously, causing drafts within the building. Revolving doors are the logical alternative to reduce this problem, but Passive House revolving doors are not yet available in the market. So the team developed a combination vestibule designed to reduce infiltration. A Passive House-certified door as the exterior entrance provides the thermal performance; it leads into a 3-meter-long vestibule, at the end of which is a revolving door. The large airport-style revolving door will afford easy access for high occupant traffic and can be folded aside in shoulder seasons, when infiltration is not a concern.
In the end, HCMA managed to successfully marry the centre’s architectural and Passive House requirements, creating a lasting tribute to beauty and efficiency. “The Passive House envelope will continue to educate people, we hope, about its environmental benefits,” says Higgs. “That’s where the magic is.”