This presentation will outline the significant cultural and site-specific challenges which needed to be identified and overcome, in order to design and build the first Passive House apartment building in Ottawa, Canada – a place known to its inhabitants as the second-coldest capital city in the world, with a climate harsher than Moscow’s.
The 42 unit Salus Clementine apartment project in Ottawa, Ontario, is Canada’s largest Passive House project to date, and the first social housing project in the country to successfully target Passive House Certification.
In reaching the Passive House energy requirement of 15 kWh/m2y, this building will exceed the energy conservation requirements of the current Ontario Building Code by a factor of 6.5, using drastically less heating and cooling energy than any other such building in Canada’s most populous province. Given the number and variety of design challenges which needed to be overcome, this exemplary building therefore sets new benchmarks for what is achievable in Canada.
As in many other jurisdictions, Passive House designers in Eastern Canada face unique challenges. Here, locally-manufactured components of Passive House quality are unheard of, and hands-on Passive House design and construction experience is still extremely rare.
Stringent fire codes in a predominantly wood-frame residential construction industry led to the choice of a light steel frame for this building, with many inherent challenges regarding thermal bridge minimization in such a cold climate. The building site orientation, along a North-South axis, could hardly have been worse, drastically minimizing the available winter solar gains, whilst increasing the risk of summer overheating on the glazed East and West facades, and driving up the insulation requirements for opaque elements and glazing. The need for a fire-resistant exterior insulation system led to significant redundancies in material costs, whilst the local Code requirement to source an approved made-in-Canada ventilation unit rather than a higher-efficiency PHI-Certified unit, led to a further significant increase in envelope performance requirements.
The exterior insulation and airtightness strategy for this building underwent several iterations, and needed to be revised again when a simple pressure test conducted by the PH design team revealed significant leakage in the OSB panels used in manufacturing the exterior-mounted SIPS panels.
Yet in spite of the challenges, this project has been notable for the ongoing determination shown by the client and the entire construction team to meet the uniquely high standards set by Passive House. All team members have been aware of and inspired by their responsibility to show that a Canadian project of this size can succeed.
Simply put: achieving Passive House performance for a project with such challenges will prove that the Standard is viable in cities across Canada for all buildings of this type.