Over the past few years, the iconic Sheraton Centre in downtown Toronto has been undergoing the largest renovation in its 50-year history. Love it or hate it, the 43-storey concrete tower has become an icon of the Toronto skyline, partly due to its distinct Brutalist architecture and partly due to its prominent location directly across from City Hall. The extensive renovations have refreshed nearly all major interior and exterior spaces of the 1300-room hotel, giving the aging landmark a new lease on life as it emerges from the Covid-19 pandemic.

The building itself is not particularly known for creating an overly friendly pedestrian environment. In fact, its solid concrete street-facing walls and car-friendly urban design make it rather intimidating to the thousands of pedestrians that pass by it every day. But a refurbishment of the two main entrances, both of which have large, glazed openings, along with the unique motor court have aimed to create a more welcoming environment for visitors, and Feature Walters played a role in bringing these areas to life.

View of the main entrance in the motor court, image courtesy of Antamex Facade Retrofits.

Feature Walters, a Walters Group company, is a steel fabrication company based out of Hamilton which specializes in architectural metals and Architecturally Exposed Structural Steel (AESS). They offer a full range of services from design through to fabrication and installation, and their portfolio comprises a diverse range of projects with a wide variety of innovative steel features. They have been producing unique architectural steel and metal products for over 50 years, and they specialize in custom-made installations that are specific to each project.

At Sheraton Centre, Feature Walters was hired by curtain wall suppliers Antamex as fabricator for the steel mullions of two prominent curtain walls on the building. Both glazed openings are at the main entrances to the building: one located on Queen Street, and the other off the motor court underneath the porte-cochere.

View of the curtain wall at the motor court entrance, image courtesy of Antamex Facade Retrofits.

For both curtain walls, Feature Walters was tasked with finding a solution on how to fabricate the unique mullions to achieve the desired look. The mullions measure an impressive 5.5 metres tall in the motor court and 5.8 metres tall on Queen Street with a slender 16mm thickness, and are fabricated to AESS 4 with a shop-applied satin paint finish. What made these mullions difficult to design, however, was their length; the maximum dimension of the raw material available was only 3.6 metres. Working within these material and structural constraints, Feature Walters was able to achieve the desired uniform look while ensuring they were structurally sound and easily constructible.

View from the interior of the motor court curtain wall, image courtesy of Antamex Facade Retrofits.

To create the full length of the mullions, two cold-rolled steel bars were spliced together by welding, and then cut and shaped to the final profile. Many rounds of testing were done to get it right, as welding is a very precise process that can lead to very undesirable outcomes if done incorrectly. It is important to establish the appropriate welding material and technique for each specific scenario, as inappropriate welds can result in distortion, shrinkage, or deterioration of the steel. Working closely with their team, Feature Walters established the appropriate welding technique, and did so with such accuracy that all of the mullions were within a millimetre tolerance of their target length.

The mullions were smoothed and finished in shop, individually packaged, and shipped to site, where they were installed as part of the curtain wall assembly. Feature Walters worked closely with Antamex to produce the unique look of the curtain walls that you see at the Sheraton Centre today. The result is simple yet striking, with impressively slender mullions framing large, uninterrupted sheets of glass that disappear into the soffit, the top rail of the glazing intentionally hidden within the ceiling cavity to enhance the verticality of the windows. The overall effect introduces a lightness into the heavy concrete walls, maximizing transparency and connecting the interiors to the public realm to welcome visitors into the hotel.

Close up image of the motor court curtain wall, image courtesy of Antamex Facade Retrofits.

More information on Feature Walters can be found on their website here. For more information on the Sheraton Centre renovations, you can check out the associated Forum thread, and you can tell us what you think by leaving a comment there or in the space provided below.


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