Heritage building restored to highest standards of environmental stewardship
Calgary, Alberta, Canada is a relatively young city, and the Calgary Public Building is a significant heritage structure from 1929. The building is a designated heritage resource, which severely limits changes to the building's exterior. The climate is also quite extreme with temperatures reaching -30°C in winter months. As such, energy conservation and efficiency are key concerns for building Owners. In this case, the Owner asked the design team to Integrate the best of modern sustainable design with respect for serious historical restoration to create a landmark facility for Calgary.
A number of techniques were deployed to assess current and future energy efficiency, including thermograph cameras, and thermal and moisture migration modelling programs. Although not entirely surprising, it was determined that the original single pane windows and the original exterior masonry walls were the largest contributors to heat loss in the building; however, the historic preservation rules demanded the exterior remain unchanged.
In response to this dilemma, the team researched, modelled and tested strategies through mock-ups and simulations for creating a second, extremely high performance envelope liner on the interior of the building without compromising the integrity of the existing building skin. This would allow the complete retention of the exterior, while achieving the aggressive energy conservation and sustainability goals of the Owner.
The key sustainable strategies were: High performance, spray applied polyurethane insulation and air barrier system; New high performance operable windows installed independently from the heritage windows on the interior; Restoration of all heritage windows for operability and natural ventilation; Use of solar energy for all domestic hot water heating; and a new high performance mechanical system incorporated within the new interior liner.
The result was a unique and quantifiable case study demonstrating that in cold climates heritage buildings do not have to be demolished or liquidated to make way for more modern, energy efficient structures. After a year of operation, the total energy consumption has been reduced by over 50%. The project shows that heritage buildings can be successfully renovated to the highest standards of environmental stewardship without sacrificing cost, energy efficiency, preservation standards or aesthetics of modern office environments.
Prime Consultant: the marc boutin architectural collaborative inc.
Consulting Engineers: Building Envelope Engineer: Morrison Hershfield Ltd. Mechanical Engineer: Stantec Consulting Ltd.
Electrical Engineer: Mulvey + Banani International (Alberta)