by Michael Tryon
The green building market in Canada is flourishing. Indeed, more than 50 per cent of building owners, architects, and contractors are reporting over 60 per cent of their projects will be green in the coming years, compared to 33 per cent of respondents in 2014, according to a recent study by the Canada Green Building Council (CaGBC). At a time when many are concerned about the environment, going green provides major benefits, including waste reduction and increased energy efficiency as well as cost savings.
Building green depends largely on the careful selection of all sustainable materials. However, identifying green products for creating a unique and pleasing architectural esthetic can be challenging. This is one of the reasons why channel glass features prominently in new structures throughout North America. Its linear, translucent appearance creates a signature esthetic, as seen at the new Fort York Visitor Centre in Toronto.
The contemporary Visitor Centre, completed in 2016, features an advanced channel glass façade. The centre became a finalist in the Mies Crown Hall Americas Prize, representing some of the most distinguished architectural works in the Americas (Founded by the Illinois Institute of Technology [IIT] College of Architecture, the Mies Crown Hall Americas Prize awards the best built work in North and South America). Having defined the centre’s façade, the translucent channel glass played a key role in securing the award nomination.
Channelling sustainability to preserve history
The Fort York Visitor Centre’s architectural team faced the challenge of preserving the historic nature of the site, while developing a contemporary venue for visitors to admire for generations to come.
Considered the birthplace of the city, the original Fort York was built in 1793. The 17-ha (43-acre) national historic landmark is nestled near the shoreline of Lake Ontario in the heart of the city’s downtown. It is the site of the notable Battle of York during the War of 1812, and is home to the largest collection of original buildings from the war.
Kearns Mancini of Toronto and Patkau Architects of Vancouver worked to enhance the appeal of the site while respecting its cultural and archaeological significance. The architects were inspired to build an abstract structure rising from the landscape, symbolically “illuminating” the history of the site.
“The approach to the visitor centre is underneath the Gardiner Expressway, which is a very large and powerful singular architectural statement, forming an almost cathedral space underneath,” said Jonathan Kearns, director of Kearns Mancini Architects. “Rather than competing with this grandiose structure, we conceptualized a subdued, yet distinct building, metaphorically connecting the fortifications and historic tapestry of the fort. We also decided to construct a transitional zone within the proposed building, creating an ascending viewing platform.”
Hundreds of feet of channel glass clad the abstract viewing platform of the visitor centre. The glass features approximately 40 per cent post-consumer recycled content. It is manufactured using 100 per cent renewable electricity and an innovative oxygen-fuelled furnace, significantly lowering carbon dioxide (CO2) emissions below the industry standard.
Channel glass is a sustainable solution going beyond its eco-friendly manufacturing. It provides a robust layer of protection to the building for decades. The durable channel glass envelope reaches continuous vertical spans of up to 6 m (20 ft), and features glass-to-glass corners in a variety of angles. Strategically positioned mid-point wind clips reinforce the glass wall and reduce deflection under high wind loads, eliminating the need for horizontal stack joints (Figure 1).
“The selection of the glass was to give a sense of sculptural quality to the part of the building emerging into the main plain of the site,” said Dan McNeil, project architect with Kearns Mancini Architects.