I attended the Les défis du bâti existant conference organized by Bâtiment durable Québec on March 28. Among the presentations, I was particularly struck by concepts that can be applied at a large scale, as the magnitude of the global decarbonization challenge makes mass solutions essential in my view.

In this regard, the first speaker, Frank Suerich-Gulick, presented the approach developed by the ReCONstruct research group, which aims to create energy retrofit principles that can be rapidly implemented across the territory. Bridging idealism and practicality, the initiative led to the idea of wrapping our aging building stock in a new, high-performance envelope. By relying on prefabrication—offering speed and optimized use of resources—while adapting solutions to each specific case through precise surveys and hygrothermal modeling, it would be possible to significantly improve the energy efficiency of a large number of serial building types (residential towers, small institutional buildings, standard industrial facilities, and others). Although this approach applies to a limited number of building typologies, it is important to note that these types are widespread and numerous across Canada (and globally). There are, of course, construction-related challenges associated with doubling the building envelope—junctions, moisture management, and cavity spaces—but human ingenuity gives reason for optimism that technical solutions can be developed to mitigate these risks.

It was also interesting to draw parallels between this presentation and the case study of the Ken Soble Tower, a 1960s residential high-rise that underwent an energy retrofit through the addition of a new, higher-performance exterior envelope while retaining the original brick cladding within the wall assembly.

Having been confronted in recent years with the difficulty of requalifying existing buildings—due to incompatible changes of use relative to the building’s configuration and capacity, as well as invasive code compliance requirements—I did not find concrete pathways at this conference to facilitate this type of project. I am therefore left with conclusions reinforced through discussions with colleagues and collaborators: namely, that it is preferable to maintain a use similar to that for which the building was originally designed and to avoid modifying load-bearing systems in retained portions of the structure. Otherwise, the extent of demolition and new construction required becomes so significant that requalification loses its meaning.

In all cases, we must persevere in finding solutions that allow us to preserve as much of our built environment as possible—not only for environmental reasons related to resource use, but also for societal considerations such as the transmission of skilled trades, the preservation of historical and identity-based values, and the quality of urban spaces.

Photo credit: Codrin Talaba / ERA Architects