Renovating a multi-family residential tower is a tall order at the best of times. But with the client’s added desire to obtain Passive House certification, a rigorous new environmental standard, the Ken Soble Tower became one of the most ambitious building restoration projects PCL’s Toronto Special Projects division has ever undertaken.
The Ken Soble Tower is an 18-story, 146-unit affordable seniors housing complex in Hamilton, Ontario. Owned by City Housing Hamilton (CHH), it was originally built in 1967 and is the oldest high-rise multi-residential building CHH’s portfolio. Many of its systems and amenities needed to be modernized — new HVAC and electrical systems, fire alarms, elevators, triple-glazed windows and a new solarium were just the start.
Key to the project was CHH’s desire to achieve the Passive House ultra-low energy EnerPHit standard, one of the first Passive House residential tower retrofits in North America. Passive House incorporates five fundamental technical requirements to ensure projects provide comfort and high performance with minimal energy use including:
- A high level of insulation in opaque wall and roof systems.
- Well-insulated glazing assemblies.
- Thermal bridge-free design and construction.
- An airtight building envelope.
- Ventilation systems with highly efficient heat or energy recovery.
To ensure that the EnerPHit standard would be met, our building envelope experts worked to optimize the constructability of the envelope design, giving the client the best value for their dollar and the opportunity to set the stage for success.
Key to envelope performance is mitigating transition risks. Transitions are the interface between two building envelope systems, such as where cladding meets a roof, or where glazing meets metal panels. Penetrations through the building envelope occur when other systems — such as mechanical, electrical, or structural components — run from the interior space to the exterior environment. Transitions and penetrations represent the highest potential for energy efficiency performance problems and require the most planning and verification.
PCL developed a detailed quality management plan that consisted of mock-ups and a rigorous testing program to make sure the building envelope’s performance was meeting the EnerPHit requirements at every step along the way. This plan also helped our trade partners understand not only how their own systems played into the larger airtightness goal, but also how their systems meshed with other trade partners’ systems. If one aspect wasn’t up to standard, regular testing allowed us to identify the problem and fix it right away, avoiding repairs that could be costly and time-consuming if we discovered the problem later in the build.
The integrated consultant team, predicted that, on completion, this building’s annual heating energy demand would decrease 91%, annual primary energy demand would decrease 78%, and greenhouse gas emissions would decrease 94%. Prior to commencing construction, PCL engaged a third-party envelope consultant to validate that the anticipated envelope performance goals were achievable. In the end, performance predications were exceeded with the Ken Soble Tower achieving Passive House EnerPHit certification in December 2021.