OGMA educates with free seminar
By Patrick Flannery
April 27, 2012 – About 50 attendees were treated by the Ontario Glass and Metal Association to an inside, in-depth view of the First Canadian Place re-cladding project at Tremco's facility in Toronto on April 26. Hamid Vossoughi and Vladmir Maleev of Halsall Associates walked the interested group through the various stages of the project from the identification and origins of the problems with the old facade through the challenges presented with the refurbishment demands right up to the implementation of the eventual solutions.
April 27, 2012 – About 50 attendees were treated by the Ontario Glass
and Metal Association to an inside, in-depth view of the First Canadian
Place re-cladding project at Tremco's facility in Toronto on April 26.
Hamid Vossoughi and Vladmir Maleev of Halsall Associates walked the
interested group through the various stages of the project from the
identification and origins of the problems with the old facade through
the challenges presented with the refurbishment demands right up to the
implementation of the eventual solutions.
The seminar was provided free of charge. Lee Baker of Tremco, an OGMA director, was instrumental in providing the large room at Tremco. Steve Gusterson of Alumicor introduced the speakers and Steve Ringler of Oakville Glass and Mirror handled the attendee reservations.
Vossoughi and Maleev began by discussing the original vision of the tower's architect, Edward Durell Stone. The building was designed in 1975 to be a significant addition to the Toronto skyline and the tallest office tower in Canada, with a number of technological features that were cutting edge at the time. For one thing, it was one of the earliest examples of structural steel tube construction. The marble cladding was chosen to create a striking white appearance that would stand out in contrast to the black- and bronze-coloured towers around it. Vossoughi noted that Stone was significantly ahead of his time with these design elements, as many of his choices are now mainstream favourites of architects around the world.
|Vossoughi said advances in glass had architects dreaming big.|
Stone chose marble as the material for the cladding because of its matchless white colour and its durability.
But what was not understood at that time was an effect called thermal hysteresis in which a substance can become permanently deformed through successive cycles of freezing and thawing. As Maleev explained, today's standards would not allow for marble sheets any less than two inches thick for this application. The sheets on First Canadian Place were an inch and a quarter. Over the next 30 years, they became so bowed that it was clearly visible to the eye and one of them actually fell off, making national news. All told, there were 45,000 marble tiles over 450,000 square feet and 9,000 IG units to replace. A third of the building's IG units had already been replaced over time by the owner as seals failed.
As Halsall began to look at the building, it found that most of the facade was in surprisingly good shape for being 30 years old. Yet several challenges were present. Many of the replaced IG units had been installed without a heel bead. Chlorides in the polysulfide sealant had corroded some of the steel frames and fasteners. Additional construction around the building since it was built had increased the wind tunnel effect to the point that the original design specs were no longer valid. And there was the question of what to do with all that discarded marble cladding. Another key consideration was how to do the monumental amount of work required in a reasonable time frame. Construction efficiencies had to be built right into the design solution. The option of cladding over the existing facade was rejected as too expensive and cumbersome.
Vossoughi said that glass "fascinates" architects because of its interaction with light and colour. Advances in glass technology are letting architects "dream big." For a solution to the First Canadian Place problem, Halsall came up with an eight-by-10-foot triple laminate glass panel using PPG Starphire clear glass with a white interlayer printed with a frit. It was decided to have the frit go all the way up the building to present the most attractive surface possible to tenants in nearby towers. Manoeuvring 800-pound panels into existing openings proved to be a difficult task, requiring the designers to come up with special anchors. Vossoughi said it is the largest use of triple laminated glass in a single project that he is aware of.
Numerous technical considerations played on the design process, including considerations for glare and how temperature changes would affect the performance of the laminating interlayer. Vossoughi made several comments about the differences between Canadian and American wind load standards, saying Halsall found it necessary to pick and choose elements of each standard to accurately reflect the conditions the tower might face. Energy efficiency was not a prime concern, but Halsall carried out a LEED analysis anyway.
The project cost in excess of $100 million. It was budgeted for seven days per floor, but Ellis Don was able to bring it down to three to four days per floor, even with heated platforms for the workers.