La Ville au cent clochers. Translated to English from French, it means the city of 100 steeples. This is the nickname given to Montreal due to its many churches and religious buildings that make up the city’s skyline, many of which feature copper as a prominent building material. For the massive 4.3 million-square-foot Centre Hospitalier de l’Université de Montréal (CHUM), this traditional material is reinterpreted as a contemporary form—it is prominent within the design of the building’s curtainwall and marks public entries.
Copper-clad project centerpieces one of the largest hospitals in North America
Photos: Adrien Williams
The Pierre-Péladeau Amphitheater is considered the crown jewel and the heart of the CHUM. Sitting at the foot of the surrounding medical towers, this triangular centerpiece is clad in perforated copper sheeting that its architects at Montreal-based Jodoin Lamarre Pratte Architects (JLPa) say “artfully reflects the sunlight during the day and emits a warm glow at night. The building envelope tells a story of layering. It articulates itself at night when moments of translucency and perforation light up components of the interior.” The copper panel supplier, fabricator and installer is Clermont Ltée, Châteauguay, Québec, Canada. Other architects working on the this and the surrounding hospital complex include CannonDesign, Pittsburgh; NEUF architect(e)s, Montreal; and Menkès Shooner Dagenais LeTourneux Architects (MSDL), Montreal.
The amphitheater can seat 365 people in its standard configuration and nearly 150 people in cabaret mode. The building also houses up to 10 meeting rooms thanks to movable walls that allow for the division of five large meeting rooms, where acoustic insulation is ensured notably by the use of triple glass. The meeting and conference rooms inside the amphitheater were intended to become “the ‘beating heart’ that generates the flow of ideas and interrelationships that contribute to the advancement of care,” says Joanne Parent, architect and partner at MSDL.
A Real Structural Feat
Jodoin Lamarre Pratte architects called designing the amphitheater a real structural feat because its volumetry and large spans were achieved by a complex load-bearing frame and cantilevered shell and floors. Built above an underground parking lot, surrounded by a perimeter circulation path with access to the parking lot, and equipped with a full-width glass skylight on the roof, this amphitheater was the source of many functional and technical challenges.
Its copper roof—supplied, fabricated and installed by Couverture Montréal Nord, St-Léonard, Québec—has a low slope of 5%; an uncommon occurrence for a project this size. Research and mock-ups were done to develop construction details that would make each copper anchor watertight along with double-crimp seals at such low slopes. Its ground level’s panels are 3-mm thick to resist impact, while the upper panels are 2-mm thick. In addition to their aesthetic qualities, copper perforated panels hide the mechanical air intakes and exhaust of the building. As there were no louvers behind the exhaust, a copper mesh has been added on the interior face of the panels as bird control.
Design adjustments accounted for weather. “The roof concept … had to be altered to incorporate a 7-foot gutter at the perimeter,” explains Olivier Millien, senior architectural technologist and technical director at JLPa, adding that “a heating cable has been installed at the base of the perforated panels to melt the snow and ice that accumulates.” The new system prevents moisture from running down the walls and protects pedestrians from falling snow and ice.
Creative Copper
Parent explains its façade “accentuates the uniqueness” of the amphitheatre. “The language of transparency that this copper skin borrows is apparent in certain places where the panels are perforated with a multitude of small circles,” she adds. “The team created a façade that blends opaque screens and fine diaphanous lace, preserving the intimacy of the interiors while maintaining a connection with the surrounding environment.”
The 194,000 perforations in the 3-mm-thick curved copper panels create a cloud of luminous rings that reflect the sun’s light during the day, but at night, filter the light emanating from within the structure to create a dramatic floating arch. In addition to creating this dynamic pattern, ever-changing throughout the day, the copper panels serve as the lateral bracing resulting in a complete integration of the components. The copper is untreated to allow oxidation over time.
The copper around the amphitheater can also be found in other aspects of the CHUM, most notably the Passerelle (bridge), which connects the CHUM ambulatory building to the neighboring logistics building. Designed as a floating lantern, it creates a sense of architectural lightness with its primary structural beams concealed above, with the floor, frame and façades seemingly suspended in air. The construction manager was Pomerleau Building Construction, Toronto; and the structural engineer was SDK & Associates Inc., Montreal.
Green Features
The copper cladding that forms the auditorium’s exterior envelope has a high recycled content, at 65% post-consumer and 35% pre-consumer. Furthermore, it is considered a regional material as the copper is sourced and the product fabricated within approximately 500 miles of the project site. As such, it contributes significantly to the LEED recycled content and regional credits.
The complex has other green features, such as efficient plumbing fixtures reduce freshwater consumption by 30% compared to a similar, standard building, plus a unique HVAC design that supplies 100% fresh air throughout the building. The research center has already been awarded LEED Gold and the hospital is aiming for LEED Silver.