Making History Again: Repurposing Maple Leaf Gardens

by Elaina Adams | September 1, 2012 9:55 am

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By Brian Burton
When the Toronto Maple Leafs moved into the Air Canada Centre (ACC) in 1999, not only was the world-famous Maple Leaf Gardens venue left empty, but there was also silence at ice level and in the seats for the first time in more than 60 years.

This classic arena––the last ‘cathedral’ still standing of the six original National Hockey League (NHL) teams––can boast some of the most incredible sports and entertainment attendance records in the world. Between 1946 (when one could purchase an upper-tier seat for 95 cents) and 1999, there was not a single unsold seat in the house. In total, more than 100 million patrons have witnessed events in the building.

Built in 1931, during the depths of the Great Depression, by sand and gravel tycoon Conn Smythe, the Gardens still retains the same appeal it had during pre-expansion times when the ‘Gashouse Gang’ (the 1930’s Leafs were called this for their off-ice antics) was the toast of the NHL.

Fast forward to 2012 and the famous facility at 60 Carlton St. has been remarkably transformed. It has been repurposed as a ‘state-of-the-art’ multi-purpose retail venue and athletic centre after Ryerson University partnered with Loblaw Companies Ltd., to transform the structure into a multi-use building. In doing so, they also managed to preserve and restore the most significant architectural heritage elements, including:

• 80-year-old ‘Art Deco’ brick façade;
• domed roof;
• windows;
• light fixtures; and
• iconic marquee above the main entrance.

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Cashbox on Carlton Street
This revitalization of one of Canada’s landmark buildings was much more than just a cosmetic renovation to an existing building. Construction on what eventually came to be known, with good reason, as the ‘Cashbox on Carlton Street,’ began at midnight on June 1, 1931. In what is still considered to be an unparalleled accomplishment, the structure was built by 1200 workers in 165 days.

The original structure required 750,000 bricks, 2006 m³ (850,000 board feet) of lumber, and 22.5 km (14 mi) of underground piping to control the ice surface temperature, all of which were purchased at bargain prices because of low demand brought about as result of the depression.

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The principal architectural firm for the design was Ross & Macdonald––designers of many well-known château-style railway hotels of the early 20^th century. Regardless of whether the building was a railroad station, hospital, bank, or hotel, the client’s expectations and building function were first and foremost. In the case of the Gardens, a principal design criteria was a good view of the action.

Structural engineering and building science challenges
The building, 13 storeys high at the top of its roof, features a concrete seating bowl topped with a structural steel-arched dome roof. The seating bowl––for 13,542 ticket-holders––by way of its shape and placement, provided lateral stability to the roof supported by immense concrete columns integral with concrete stair towers at the four corners of the building and exterior walls. Demolishing the seating meant both the exterior walls and roof would lose their essential lateral support.

The principal challenge was to retrofit the building’s structure and interior, while ensuring the exterior walls did not collapse during seating, concourse floor area, and box seat removal. Replacing these components was to be a grade-level Loblaws supermarket and two additional floors for retail and athletic use, including a second-floor gymnasium, a third-floor ice rink, and below-grade parking.

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Ship in a bottle
The project entailed solving a variety of complex structural engineering challenges. The structural and geotechnical consultant for the renovation was exp—a multi-disciplinary firm that had been associated with the facility since the early 1960s and had intimate working knowledge of the existing structure.

“Re-adapting the Gardens could be compared to building a ship in a bottle, except the bottle already contained a ship which, by necessity, had to be dismantled piece by piece—without breaking the bottle,” explained Paul Sandford, exp project principal engineer.

While the original building interior was demolished and removed, the stability of the structure and exterior walls was maintained by installing temporary steel bracing within the original concrete frames at the building’s east and west sides. At the north and south ends, large box trusses––3.4 m (11 ft) deep, 8.5 m (27.9 ft) wide, and spanning more than 66 m (216.5 ft)––were installed between the existing buttresses at the facility’s corners.

With the new underground parking level specified 3.4 m below-grade at the south side and up to 7 m (23 ft) below-grade on the north side, significant portions of the exterior foundation walls required underpinning using a combination of traditional underpinning, helical piles, micro-piles, and soil-nailing. At the corner buttresses, which supported the entire roof’s weight, temporary caisson walls were installed adjacent to the footings to laterally support the soil under them while the surrounding area was excavated down to the parking level. Basically, an entirely new structure was fabricated inside the four walls and connected to the existing structure to provide lateral support for the restored building.

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Throughout the restoration, the existing structure and exterior walls were remotely monitored on a continuous basis for any movement through the innovative use of a proprietary computerized fibre-optic technology. Engineers worked closely with the demolition contractor and exp to fine-tune the computerized monitoring technology setup to ensure alarms would sound and work could be stopped immediately if movement or vibration exceeded a pre-determined safety threshold.

Once the new interior structure was constructed and connected to the original exterior façade systems, the temporary bracings were carefully removed. Since stability was now provided by the new structure within the original shell, large openings could then be cut into the corner buttresses to accommodate a parking ramp and main entrance. The new loading-dock door installed through the north wall required removal of four concrete columns that supported both the north wall and the roof. In the end, exp engineers were successful in solving the formidable structural engineering challenges of the historic building’s redevelopment.

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Retaining heritage elements
ERA Architects was retained as the heritage architects at the project’s earliest stages to consult on the range of modifications to the original building, which is designated as a National Historic Site under the auspices of Parks Canada. ERA supervised the alterations to the designated heritage fabric and directed the restoration of the retained heritage elements. The company also prepared a heritage interpretation plan (HIP) to ensure the building’s history was celebrated throughout the spaces that would be occupied by the new owners. Additionally, ERA designed the replicated Carlton Street marquee using archival photographs.

Will MacIvor, ERA project architect, says about one-fifth of the bricks were repointed during the restoration. In cases where bricks were damaged or cracked, much of the replacement material was salvaged when it was removed to accommodate the new openings that were created for loading bays and air intake vents. When additional brick was required, salvaged brick that was tinted slightly to match was acquired from the R.C. Harris water treatment plant located in eastern Toronto that was built at approximately the same time as the Gardens.

According to MacIvor, the original 1931 drawings helped ERA with various aspects of the design, including the ornamental metal work components with the horizontal banding and octagonal window drops. The upper-level fenestration components were refitted with double-glazed vintage steel industrial windows. ERA restored 12 original windows while the remaining units were manufactured to match the original ones.

MacIvor also explained not all elements were kept entirely intact because of the dramatic structural modifications to the interior.

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Opening the new Gardens
Although the construction speed garnered most of the headlines while it was being built, construction of Maple Leaf Gardens was a marvel in the application of building science expertise.

Few realize almost all enclosed stadiums and arenas have roofs supported by columns that obstruct the view of at least some of the spectators. Maple Leaf Gardens is one of the few that had none. This was accomplished in an era when computers were unavailable and the innovative roof design involved constructing trusses where one corner was ‘pinned’ while the other three rested on rollers, allowing the structure to expand and contract in response to temperature changes.

Designing a roof at that time with the weight of 0.67 kPa (0.097 psi)
was unheard of, and this was just one of the innovations in building science and technology that almost certainly reflects Canada’s long-standing reputation as a world leader in cold-weather building science.

“We are very proud to have been involved in the redevelopment of this historic landmark,” says David Tippler, vice-president of Building Design. “While the technical challenges were rewarding to us as engineers, the opportunity to restore the vibrancy of this building for the community is even more gratifying.”

Conclusion
Maple Leaf Gardens was built for approximately $1.5 million in 1931. This significant adaptive reuse project, aside from preserving and restoring one of Toronto’s best-known landmark buildings, can be expected to generate several million dollars in economic activity for the city and the immediate neighbourhood over the next 20 years and beyond.

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Although it seldom receives recognition as such, construction is Canada’s largest industry and biggest employer. The continuing investments, combined with ongoing efforts to repurpose the existing building stock and commitment to designing efficient, sustainable buildings is almost certainly one of the factors that has allowed Canada’s economy to perform so well relative to many other nations. The remarkable restoration of Maple Leaf Gardens is a case in point.

Brian Burton is an R&D specialist for consulting firm exp. He has published more than 450 articles on building and landscaping science. Burton writes a regular column for Glass Canada entitled “Fenestration Forum” and is a regular contributor to Canadian Home Inspector Magazine. He was recently appointed to Canadian Standard Association’s (CSA’s) Fenestration Installation Technician Certification Programs Personnel Committee. Burton can be reached via e-mail at brian.burton@exp.com.

Source URL: https://www.constructioncanada.net/making-history-again-repurposing-maple-leaf-gardens/

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