The Grand Théâtre de Québec’s new glass envelope is a truly innovative solution from an
architectural, structural and mechanical point of view. It will ensure the long-term sustainability of a central piece of Quebec City’s modern heritage.By adding a transparent, immaterial and structural layer to the original theatre, this refurbishment solution by Lemay and Atelier 21 protects and preserves the building’s two distinguishing components: its brutalist architecture by Victor Prus and historic, sculptural mural by artist Jordi
Bonet. Famed for both, the building is a prized cultural icon inaugurated for Canada’s Confederation Centennial on January 16, 1971. Prefabricated concrete indoor and outdoor walls are the theatre’s defining feature, and nearly 60% of the interior is covered by Bonet’s mural. There were multiple constraints to consider in designing and creating the glass envelope. At the time of our involvement, moisture had caused the concrete panels’ anchors to disintegrate. Any alteration had to be severely limited; the building’s fragility, and the inability to directly access the concrete anchors, were additional challenges. With the mural being intertwined with the exterior concrete panels, any operation also had to have zero impact and vibration on the envelope. Some 900 glass panels, each weighing around half a tonne, now encapsulate the Grand Théâtre. An independent structure transfers the new structural loads directly to the existing foundation walls using structural brackets, which greatly reduces the loads on the building itself. The construction systems were almost all custom-designed. Fitting the unusual shape of the Grand Théâtre required extreme design and manufacturing precision. The team performed extensive computer, energy and computational fluid dynamics (CFD) simulations, strength testing and assessments of the space between the structure and the glass wall; humidity, lighting and other tests, followed by adjustments down to two-millimetre precision. The plaque-assembly and joint-structure testing alone led to our development of the panels’ custom silicone joint base.
Many of the techniques applied to achieve this level of precision were used for the first time in
North America. For instance, two-tonne sand trays were hung at the bottom of the structure to simulate the weight of the heavy transparent panels before they were affixed; workers were thereby able to make sure that the structure was in precise position before adding the glass. Each time a pane was installed, ballast was removed to maintain the balance of the whole structure.The delicate steel structure, on which the glass rests, is the result of intense and sustained teamwork among architects, engineers, construction specialists and manufacturers, who designed a revolutionary structure while respecting the project’s budget. This involved creating custom prefabricated fasteners to maintain the transparent aspect of the new protective layer and minimize the visual impact of the aluminum plates supporting the glass. In-depth reflection was necessary to meet structural, climatic, heritage and implementation requirements. The construction system also had to allow for maintenance via a suspended nacelle inserted between the existing building and the new envelope. Because the glass needed to be affixed onto the steel structure, the steel could not be exposed to any significant temperature variation between the moment of its own on-site adjustment and the installation of the glass.The project was fast-tracked, with work on the building proceeding during daytime and evening theatre operations. Construction noise could not be produced during shows or rehearsals; architectural and technical solutions could not hinder building access. Coordination with several levels of decision-makers was essential. Weather conditions were also a major challenge: installation of the new envelope was only possible under specific climatic conditions. The solution shields the theatre from the elements by creating a secondary, tempered envelope housing a low-flow heat recovery and thermal mass system. The system is both energy-efficient and economical. The new layer now acts as an extension of the original building it protects, using the same finely tuned structural logic and composition. This complex, delicate rescue operation has maintained the continuity of the original design storyline, now featuring a thin wall of immaterial, protective glass. The brutalist lines and artistic narrative are even more striking thanks to this subtle, functional and ecologically viable solution.
As intended, the newly created construction void between the glass envelope and outside walls eliminates the migration of exterior moisture through the concrete and, most importantly, halts its corrosive effects. Compared to a more traditional solution, the project minimized the extent of the refurbishment work, site excavation and material use while remaining economical.Bold and innovative on several levels, the Grand théâtre de Québec is a North American first to completely encapsulate a building this way. Responding to a very particular context, it proved to be the best solution to meet sustainability and preservation criteria
Lemay has been imagining new ways to create spaces that engage users and bring people together since 1957. Over 450 architects, designers and change-makers work together to cultivate innovation in their own backyards and in communities around the world. The firm finds its strength in transdisciplinarity, and has developed its very own Net PositiveTM approach to guide teams towards sustainable solutions that shape a better future. With the human experience at its heart, Lemay strives to embraces constraints and build spaces to grow.
Atelier 21 is an architecture firm established in Canada since 2004. Pursuing excellence to conceive quality works that will last trough time, this group of experienced architects works in the fields of green architecture and heritage, old or modern, in a vision of a responsible use of the natural resources. Atelier 21 offers a recognized expertise in institutional and commercial architecture as well as envelope refurbishment.