Located near the serene Don Valley Ravine in a northern neighbourhood of Toronto, Canada, the West Don Ravine Passive House prioritises views of the natural landscape and sustainable design. Designed by Canadian practice Poiesis Architecture, the private residence is built to resist climate change upon the request of the clients, incorporating passive design techniques. Reducing up to 90 per cent of energy consumption, it is the first house in the city to receive the Passive House certification from the PHIUS organisation.

“Passive design presupposes that the future of our power sources will be electric and renewable,” says Canadian architect Gregory Rubin, founder of the 2016-established practice. “The ultimate goal is to future-proof your building and the first step towards doing that is to create a super-insulated building that dramatically reduces the demands of the mechanical systems,” adds Rubin. Specialising in innovative urban housing, public realm interventions and energy efficient building, the architects strive to balance sustainability and social responsibility.

With the demolition and site preparation paused because of the pandemic, Rubin saw it as a chance to explore the native vegetation of the site. After partnering with an urban forestry consultancy specialising in ravine stewardship and ecological restoration, the architect was granted the Pollinator Steward Certification. To attain the Passive House certification, the architects collaborated with a team of technical engineers—experts in Passive House standards and envelope design—to implement the HVAC system. Openings were carefully integrated with the high-performance envelope of the building comprising super-insulated and airtight assemblies, regulating temperature and humidity levels within the spaces. Additionally, the architects employed a consultant to integrate the shades and lighting with the home automation system, directing the innovative design towards an ‘all-electric future’.

The residential design, dictated by ecological mandates, takes shape within the same footprint as the previous building, replacing hard material surfaces with native plants. Considering the impact of construction on the health of the users and nature, the architects thoughtfully select materials for the architecture and interior design of the house to create a healthy built environment. “I would describe the design as ‘modernism harmonised with sustainability’, where health-focused principles go hand in hand with comfort and energy efficiency,” explains Rubin.

Addressing the orientation and slope of the site, the upper level of the house is accessible from the street through a modest entrance in the south. While the upper floor houses the garage and master bedroom, the lower level comprises the living, kitchen and dining areas. The common areas lead to the outdoor pool and garden terraces that cascade towards the ravine, fostering a deeper connection with the natural landscape.

Clean lines, simple forms and minimal design characterise the design language of the residential architecture. Spatial functions and ecological design concerns inform the size and position of doors and windows in the building. The south facade design is understated with thoughtfully positioned windows to allow natural light to percolate the indoors. As the building faces the ravine in the north, a glazed wall captures the view of the outdoors, providing excess to the garden. Balancing the heat gain from the glass facade, the architects use materials such as terracotta and exposed concrete for thermal regulation. The relationship between the building’s openings, material selection and sloped roof design demonstrate their efficacy in maintaining thermal comfort during various weather conditions.

Surface finishes play an essential role in the building’s sustainable design model. While terracotta baguettes and tiles adorn the exterior walls and private zones, locally sourced limestone distinguishes the common areas. “We decided to apply the insulation on the exterior of the envelope, which opened the door to exposing the concrete foundation wall on the inside,” reveals Rubin. For the private areas such as bedrooms, the architects use materials such as ash wood, jack pine and white pine for flooring and wainscotting.

“The emphasis on Passive House design isn’t about simply applying the latest and greatest technology, but rather on committing to building something durable, resilient, and well-insulated,” revealed Rubin in the press release, “as a consequence of those initiatives, both operational and consumption demands can be significantly reduced.” Following the rigorous collaborative efforts behind the project, the architects shared a ravine stewardship programme with the residents of the neighbourhood, to imbue and inspire them with a greater understanding of the ecosystem they inhabit.

The West Don Ravine Passive House, though seemingly simple and understated, is meticulously built with great care and complexity through consistent collaborative efforts. The contextual architecture is considerate towards the comfort of its residents and the long-term effects of the construction on the ecosystem of the ravine. By addressing environmental concerns through science, technology and modern architecture, the architects present a glimpse of the homes of the future, where the interests of humans and nature align in harmony.