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The Ken Soble Tower

EnerPHit transformation lights the way to new retrofit model

By Graeme Stewart

The project is not only the first such retrofit in North America but, at 18 storeys and more than 7500 m2, it is one of the largest EnerPHit1 certified projects in the world. In the Canadian context, it is also arguably the most successful to date in meeting the goals of the Federal government’s National Housing Strategy Repair and Renewal Fund.

The modernization of the building has reinstated 146 units of affordable seniors’ housing, while reinvigorating community spaces and outdoor gathering areas, enabling aging-in-place throughout, and barrier-free living in 20% of suites.


The Ken Soble tower was originally constructed in 1967 and by the start of this project had fallen into a state of disrepair and was uninhabitable. One of the considerations at the outset of this project was whether to demolish the existing structure and build new, or to complete a retrofit and restore the building to a serviceable condition, consistent with today’s standards of durability and performance.

Ultimately, the team decided to retrofit which extended the life of the existing building’s cast-in-place concrete frame and part of the existing masonry envelope. The environmental impact and embodied carbon of the original construction were not wasted, nor unnecessarily duplicated in a new building.  Through the Passive House level retrofit, the ongoing operational carbon emissions were drastically reduced and will support an extended service life.

Retrofit Strategies

Operational carbon reductions are achieved using a high-performance envelope, with nearly twice the insulation value required by Code, drastically reducing heating and cooling demand. The envelope upgrades include R-38 effective over cladding, passive-house certified windows and air sealing details to achieve 0.6ACH @50Pa airtightness.

Project Credits

  • Owner/developer  City Housing Hamilton
  • Architect  ERA Architects
  • General Contractor  PCL Constructors
  • Landscape Architect  ERA Architects
  • Electrical Engineer  Nemetz & Associates
  • Mechanical engineer  Reinbold Engineering
  • Structural Engineer  Entuitive Corp
  • Commissioning Agent  CFMS West Consulting Inc
  • Passive House Consultant  JMV Consulting
  • Passive House Certifier  Herz & Lang Gmt
  • Building Envelope Consultant  Entuitive Corp
  • Photos  Doublespace Photography

The renovated tower offers a built example to improve dramatically the performance of the thousands of similar apartments across North America. The AlphaGuard™ liquid-applied roofing system by Tremco Roofing helps to maintain the integrity of the building envelope.

The finished façade with new Juliette balconies. EJOT® CROSSFIX® stainless steel thermal clip brackets in the facade system help to maintain thermal performance.

Graeme Stewart is a principal at ERA Architects.