With sustainability and building performance top of mind, PCL was enlisted to revitalize a 50-year-old apartment tower into a groundbreaking Passive House retrofit, one of the first retrofits of this kind in North America. Ken Soble Tower officially achieved EnerPHit certification in December 2021, making this the largest residential EnerPHit-certified project in the world.

Awarded by the Passive House Institute, EnerPHit is an internationally recognized certification program for building retrofits that meet ultra-low energy standards. Achieving this advanced energy performance standard is a testament to the integrated collaboration and expert rigor that went into the envelope design and construction.

Originally built in 1967, Ken Soble Tower is an 18-story, 146-unit seniors’ housing complex with a three-story annex owned by CityHousing Hamilton.

Beginning construction in July 2019, PCL demolished exterior windows and doors, balconies and select components of the interior and modernized the tower’s building systems and amenities including new air handling units, insulated mechanical piping, electrical systems, fire alarms and elevators, as well as a new solarium and a restored site landscape.

To ensure the tower provides comfort and high performance, all while using minimal energy – key to Passive House certification – PCL also installed a new high-performance building envelope on top of the existing masonry walls. The new envelope included adding a continuous air barrier throughout the envelope, significant amounts of insulation and triple-glazed high-performing windows, while eliminating the thermal bridges from the balconies and all other areas of the envelope.

The project achieved substantial completion in April 2021 and will provide the Hamilton, Ontario, community with high-quality, affordable housing.

Guided by our in-house envelope engineering specialist, sustainability and building systems engineers and experts, PCL was quick to benchmark the levels of planning and communication vital for achieving EnerPHit certification.

The certification process challenges traditional construction planning and, specifically, demands early integration of experts into the design development process. These experts guide the envelope design and performance specifications from first principles.

The need for enhanced quality management and performance testing meant increased communication and collaboration between client, consultants, trades and PCL’s in-house experts and construction specialists. We worked with our design and trade partners to ensure the design met stringent Passive House requirements and the work could be done on budget and on schedule. Our team developed a detailed quality management and testing program to ensure the building envelope’s performance was meeting air tightness requirements every step along the way.

“Regular testing allowed the team to identify and fix problems right away, avoiding repairs that could be costly and time consuming if problems were discovered later in the build,” explained Lori O’Malley, PCL’s in-house building envelope engineering specialist.

The team jubilantly celebrated success when it conducted and passed the whole building air tightness test in March 2021, well exceeding the established performance.

“Receiving EnerPHit certification is a major accomplishment with many lessons learned that will guide future Passive House projects across PCL and the construction industry,” said Marc Pascoli, vice president and district manager of PCL Toronto’s office. “The project’s impact reaches beyond construction. Ken Soble Tower is a sustainable and innovative way to provide livable homes for the community, and we are proud to have been part of this unique project.”​​