University of Victoria Student Housing + Dining, Victoria, BC

Precedent-setting Passive House Design 

The buildings (officially named Čeqʷəŋín ʔéʔləŋ or Cheko’nien House and Sŋéqə ʔéʔləŋ or Sngequ House) were designed to Passive House standard, and if certified, will be among the largest Passive House buildings in Canada and the first Passive House buildings at the University of Victoria. With super-insulated and airtight envelopes, both exceed Step 5 of the BC Energy Step Code—the highest level for efficiency in the province. The project also includes the largest commercial kitchen ever integrated into a Passive House building. A significant endeavor in the energy reduction strategy and a first of its kind globally, it is six times more efficient than a conventional kitchen. Like the buildings themselves, the kitchen, which serves over 8,700 meals a day, is almost entirely electrically powered in keeping with the University’s goal of reducing its GHG emissions and reliance on fossil fuel energy sources. The design and construction of the UVic Student Housing + Dining project is reflective of the University’s commitment to a low carbon future as outlined in the UVic Climate and Sustainability Action Plan 2023, which aims to bolster climate action and sustainability while advancing the United Nations Sustainable Development Goals (UN SDGs). 

The Goal: High performance, low carbon buildings that prioritize wellbeing 

In collaboration with the Passive House Institute in Germany, the team worked nearly a year and a half on a design that would meet the project’s ambitious goals. In addition to targeting Passive House certification, the complex is also targeting LEED v4 Gold. Both Cheko’nien House and Sngequ House represent best practices in energy-efficient, sustainable design, while emphasizing occupant comfort and wellbeing, social connection, and engagement. With construction of the new buildings, the team sought to achieve a number of key goals, including: radical energy efficiency, extremely low operational carbon, reduced greenhouse gas emissions, as well as superior thermal comfort and indoor environmental quality. The University of Victoria also sought to address climate change by building for resiliency to 2050 climate projections, futureproofing in terms of performance, while also endeavoring to meet UVic’s climate commitments to the Clean BC Plan and its commitments outlined in the university’s Sustainability Action Plan. The modelling was conducted by the University’s Pacific Climate Impact Consortium (PCIC).  In keeping with the Passive House standard, the buildings also prioritize wellbeing and sustainability through careful material selection in an effort to reduce both operational and embodied carbon. In addition to stone wool insulation which offers a number of beneficial properties inherent by nature, the building integrates an array of sustainable materials, including the prominent use of locally-sourced mass timber and wood products.  

The Challenge 

With a wide array of challenging, high-performance goals, the project was complex, necessitating a very holistic approach. While the rigorous energy targets remained at the forefront, the project teams also had to balance additional considerations that factored significantly into the design, including fire protection, moisture management, climate resilience, durability, air quality, circularity, transparency, acoustics, and more. While active systems played an integral role in minimizing energy demand, the integration of passive measures, as the Passive House standard implies, were also important to efficiency outcomes.    

The Solution 

Stone wool insulation provided the key to meeting a wide variety of identified objectives. The project incorporates 8” of Cavityrock continuous exterior insulation into the exterior wall system to serve a number of important functions. Primarily, the stone wool meets the need for high insulation levels, which passively work to maintain consistent temperatures inside the building, providing occupants with reliable thermal comfort while reducing demand on energy-reliant mechanical systems. Stone wool also served to address long-term resilience and durability, particularly as the buildings will need to stand up to more extreme weather events due to the impacts of climate change. Creating a durable structure with robust materials and a higher-performing building envelope will potentially help reduce maintenance and/or remediation/replacement/repair costs during the building’s long-term operation.

Victoria’s coastal and temperate climate increases the risk of temperature extremes and heavy precipitation, based on the PCIC 2050 climate modelling. Even amid construction, the area experienced an atmospheric river event, a condensed band of water vapor that produces heavy amounts of rain or snow that typically stalls over land to create the potential for record precipitation and flooding. With climate change in mind, the design team focused on a ventilated rainscreen strategy. Because stone wool insulation is vapor permeable and allows any moisture to dry to the outside, it will help keep the wall system dry, mitigating any potential moisture-related issues over the life of the building. Stone wool’s inorganic composition and resistance to mold and mildew also contribute to the buildings’ excellent indoor environmental quality (IEQ), including healthy indoor air quality.  With moisture addressed, fire protection was another aspect pertaining to building resiliency that the design team aimed to address.  As a student residence and high-occupancy building, fire safety measures were considered essential. Stone wool was selected since a non-combustible insulation product was desired.  In addition to the rainscreen, stone wool insulation also satisfied the requirement for a fire-rated wall assembly where an exterior canopy was incorporated to create a covered loading area on one of the buildings. Stone wool products offer high fire resistance to temperatures up to 1,177°C or 2,150°F, and the specific products chosen boast the lowest possible smoke development and flame spread index of 0/0 when tested to ASTM E84.  Moreover, stone wool achieves its fire resistance due to its natural stone composition, without the need for added chemical flame retardants. When it came to product selection in all applications, use of natural, healthy, and sustainable materials was a goal consistent with the University’s Sustainability strategy.

Materials were reviewed against Perkins&Will’s  Precautionary List  and the architectural and design team reviewed EPDs, Lifecycle Assessments and transparency statements to ensure harmful materials were excluded and sustainable options were prioritized. Stone wool insulation appealed due to the use of natural raw and recycled materials in its production, its ability to help lower operational carbon, its long-term performance, and its circularity profile, combined with its ability to contribute to other key performance goals.  While the design team didn’t pursue LEED points in the acoustics category, the density of stone wool is expected to help enhance the occupant experience, reducing outdoor to indoor sound transmission for quieter spaces—an important factor given the complex’s intended use as student residences, academic/classroom and meeting spaces.

From a contractor perspective, stone wool provided a number of advantages that helped during the insulation install. The density and dimensional stability of Cavityrock®allowed for excellent handling. As the insulation was installed in two, 4” layers, these two characteristics also ensured tight seams to prevent gapping, which made it possible to achieve a more precise install. The dimensional stability and tight fit also provide confidence that the material will stand up over time, with no compromise to the building’s thermal, fire, or acoustic performance.  Density once again factored into another big benefit to the install teams: ease of install. The Cavityrock® boards were ideal to cut and custom fit, as needed, and worked well with other components including the steel clips and galvanized girts. The properties and benefits that stone wool insulation offers ultimately resulted in time saved on the jobsite, helping install teams adhere to the tight construction schedule.