Behind the Project: Bridlewood Affordable Housing
Entuitive was retained by MTA | Urban Design Architecture Interior Design Inc., as the Building Envelope Consultant on this project.
Thanks so much for sitting down with us, David. Can you tell us about this project?
David: Thanks for having me and of course. The Bridlewood Affordable Housing project is part of the Calgary Housing Strategic Plan that created 62 new affordable housing units in the community of Bridlewood. The development also includes 16 four-bedroom townhomes, 30 two-bedroom townhomes, and 16 units of two-bedroom stacked townhomes, eight of which are barrier-free and include a shared amenity space, community space, kitchen, washroom, small laundry, waste management facility, and green space.
What were some of the technical challenges on this project?
David: The main challenge on this project was developing an affordable housing complex that met the City of Calgary’s sustainable building policy, which required the performance of the buildings to be 26% better than the National Energy Code of Canada for Buildings (NECB) 2011.
Prior to the Bridlewood project, these new codes were not yet in place, and in our experience the adoption of the codes shook up the industry a bit, though they didn’t fundamentally change the design process to consider performance first or at least in tandem with the design. For this project, the team undertook a new way of collaborating early in the project and throughout the design phases to achieve the energy targets outlined. The goal of the new energy code is to eventually get to a place of net zero energy for all new builds.
To solve this challenge, we worked collaboratively with all stakeholders, including the City of Calgary, MTA, the electrical and mechanical sub-consultants, and the City’s energy analysis consultant.
As with all energy-efficient projects, we have to be cognizant of budget and constructability. As such, together with the energy modellers, our team evaluated dozens of options for the building envelope, the windows, the siding, and the roof. Since this was a newer design process, we wanted to provide as many options as possible.
Collaborating with the energy modellers, we were then able to find the most optimized design for the project to exceed the energy code targets in a cost-effective and constructible manner.
What were some of the methods and materials the team settled on to ensure energy code compliance?
David: We used a building envelope system not commonly used in wood-frame construction. This included high-performance air barrier continuity, using more insulation and aligning the thermal plane of the windows with the walls, ensuring low exterior sound transmission, and improved condensation resistance and overall thermal performance, as well as inclusion of exterior insulation on the foundation.
In terms of the air barrier continuity, typically the polyethylene is taped and sealed and would be used to seal the windows on the inside of the structure. In this case we moved that air barrier to the exterior of the wall assembly. This may sound like a small detail, but it actually makes a big difference!
If you think about a typical residence, tenants will usually hang pictures, shelves, and hooks on the wall, punching through the wall to do so and in turn, the polyethylene. These holes typically are not filled in correctly prior to the next tenant. Over time, this results in reduced performance via air leakage. Moving the air barrier to the exterior was an effort to improve long-term performance, reduce that loss, and ensure that the building performance would remain the same from day one to day 1,000 and beyond.
In addition, by using more insulation and a different type of insulation than usual, we ended up sinking the windows into the walls more, which also creates an interesting architectural aesthetic. Previously we would have used a regular fiberglass insulation, but for this project we used mineral insulation. This type of insulation provides better sound transmission reduction and increases thermal performance.
Finally, we added exterior insulation to the foundation, which is also an uncommon technique that has been developed to meet more stringent energy codes.
Wow, it sounds like many “little” and not so little changes were necessary to ensure an energy efficient building envelope for this project, requiring a whole new way of working and thinking about affordable housing projects.
David: Absolutely. Finishing the project really felt like a big win. I’m really proud of the collaboration on this project. We all came together to understand how to develop an improved process for moving through each stage of the project, which has set us up for success on similar projects in the future. Of course, deep collaboration is the Entuitive way, and those types of projects are always the most rewarding. It really requires us to understand our client’s needs, the architect’s aspirations, and what the rest of the team had to focus on.
Thanks so much for sitting down with us, David!
If you’d like to learn more about the Bridlewood Affordable Housing project, or about Entuitive’s work on other similar projects and our Building Envelope work, reach out to David Leonard.