Dedicated to sustainable,
high performance building

Bois Ellen Housing Co-op

Construction detailing and energy efficiency on a budget

The recently completed Bois Ellen Co-op is located in the City of Laval near the Place de la Concorde train and metro station, a neighbourhood that is in transition toward multi-residential housing. Contrary to current trends that rely heavily on active renewable technologies, the design that emerged from the Integrated Design Process [IDP] focuses on passive design measures to ensure that ongoing maintenance is easily manageable
for the Co-op and its residents.

By Daniel Pearl and Cecilia Chen


The L-shaped building has a six-storey senior’s wing along Avenue Robert-Élie [with a dining hall opening to a central courtyard] and a 13-storey wing along the north-west edge of the site. Housing both seniors and families, Bois Ellen integrates knowledge, experience, and critical lessons learned by the architects on their previous large-scale community housing projects.

What may prove to be the most valuable aspect of the project is the deliberate strategy to encourage the residents of Bois Ellen to become the advocates for this creative and affordable housing model with the hope that it can be replicated across Canada. This strategy emerged from open dialogue and active listening between the design team and the residents.

Both wings are cast-in-place concrete structures clad in a combination of brick and metal panels tied back to light steel framing. The technical innovations at Bois Ellen are focused on three major themes :

  • a significant improvement in building envelope performance – with an ‘exterior blanket’ approach to insulation, promoting energy efficiency, thermal comfort, and excellent building air-tightness, rarely seen in Canada for affordable housing at this scale
  • the simplification of the buildings’ mechanical systems—including heating, ventilation and dehumidification;
  • a pro-active, streamlined approach to passing on building operations to the residents via education sessions, ongoing dialogue, continuous monitoring, iterative adjustments, and gradual handover of the various procedures for the different seasons and circumstances.

The project was completed on budget, with a premium less than seven percent above conventional affordable housing.  This included an extensive life cycle analysis of the building envelope, and enhanced quality assurance procedures.

The envelope design incorporates clear and careful detailing, as well as specifications to increase effective thermal resistance and comfort; investment in the best window and door units within the budget, with coatings tailored to solar orientation; window and door installation details that increased comfort and reduced thermal bridging and condensation risks; insulation placed fully outside of the steel stud wall structure  spanning between concrete floor slabs; reduction of thermal bridging with non-conductive materials  at girts and sub-girts [specifically, the use of fibreglass ‘Cascadia Clips’ which significantly reduce thermal bridging compared to a more traditional metal girt cladding system], thermally broken cantilevered balcony structures using rigid insulation and fibreglass re-bar; solar-shading devices on south-westerly façades; and careful insulation and air-tightness at all exterior wall penetrations required  for electrical and mechanical systems.

Key to meeting and exceeding the Passive House standard for air-tightness  was the pride taken by the trades responsible for building the exterior envelope. The co-op was fortunate to have a general contractor excited by the envelope challenge, and motivated by the specified performance clauses and penalties.

Daniel Pearl and Cecilia Chen are with L’OEUF s.e.n.c architects.

  • Funding/Support Organizations
    Energy Pilot projet/projet novateur  Société d’habitation du Québec
    IDP process and Documentation  Canadian Mortgage and Housing Corporation;
    Monitoring Equipment and Project Monitoring  NRCan CanmetENERGY and Hydro Québec
    Monitoring and resident education  Frank Suerich-Gulick
    Technical Resource Group  Reseau 2000+
  • Project Credits
    Client France Clavette, Présidente COOP Bois Ellen
    Architects L’OEUF s.e.n.c. architectes in consortium with Giasson Farregut architectes
    Mechanical & Electrical Engineers Pageau Morel et Associés
    Energy Design Simulation and Analysis Consultant EnerSys Analytics Inc.
    Structural & Civil Engineer Nicolet Chartrand Knoll
    Landscape architects Beaupré associés
    General Contractor Sept Frères Construction G2 Inc.
    Photos Corey Narstead, CM Images and Daniel Pearl – L’OEUF