Volume 47, Issue 11 - November 2012
Comment On This Story
A glass supplier’s biggest competitor isn’t necessarily another glass company; often it’s another building material, such as stone, brick or metal. But, when it came to re-cladding the original Carrara marble façade of Toronto’s First Canadian Place (FCP), it was glass that won the job.
Originally constructed in 1975 and designed by Edward Durell Stone and Bregman+Hamann Architects, FCP is the tallest office tower in Canada. It was built with white exterior cladding created with more than 45,000 marble stone veneer panels. Over the years, however, the marble began to deteriorate and the owners, Brookfield Office Properties, decided an updated façade was in order. In 2007 the decision was made to replace the stone veneer. That call went to Moed de Armas & Shannon, a New York-based architectural firm experienced in re-cladding projects.
“This is an iconic structure in the city,” says Dan Shannon, a principal with Moed de Armas & Shannon. “We were chosen to be the design architects and with Bregman+Hamann as architect of record, we worked to not only fix what was failing but also re-define the building.”
Shannon says there were three goals for the program. The first was to deal with problem at hand—the stone was failing. The second was to redefine the building as a prominent part of the Toronto skyline. And the third was to give the building a target lifespan of 50 years. “We embarked on a process to find a way to replace 45,000 panels of marble with 5,000 panels of the whitest, largest glass that we could—white was important because the building was originally white and we did not want to change that,” says Shannon, explaining that they wanted to use glass for several reasons.
“One was the size; we could not get a stone panel at 8- by 10-feet. Also, we wanted the reflections and various changes that the building can take on during the day, from reflecting the sun to reflecting the city to the shades and shadows, etc. in the evening,” says Shannon. “We wanted that activity. We also wanted the flexibility in terms of [not only color] but also pattern.”
FCP was originally designed by famed architect Edward Durell Stone who was very involved in applying geometric patterns to his buildings.
“We wanted the glass to add texture and give richness that underlies the use of the stone. We did not want to lose the richness of the marble with just a plain white piece of glass. We wanted depth, and of course we wanted performance,” says Shannon. “We wanted to achieve our goal of a 50-year lifespan and we knew we could do that with glass.”
But there was a problem: such a glass did not exist.
“So we embarked on a nearly year-long technical study and research using everyone and every resource we could, from colleagues in Canada to worldwide glass manufacturers, to [consultants],” says Shannon, adding that Dr. Scott Norville from Texas Tech University played a critical role.
“He was very important on this project in terms of dealing with capacity on glass because we had winds in excess of 100 mph at the top of the building,” says Shannon.
“Dr. Norville was the one who wrote the paper and did the experiments to show that laminated glass assemblies could perform and how you could assess these strengths under these loads,” says Shannon. “He was essential because his study on laminated assemblies is the only one that shows how you can assess the load resistance of interlayer glass.”
According to Shannon, going from the outside in, the glazing consisted of Starphire glass and with a ceramic frit on the #2 surface. Next to that was a clear interlayer, into which Shannon says a lot of research went into finding, as it was critical to find one that would not discolor the white; it was ultimately supplied by Trosifol. Next was another clear layer of Starphire glass and then a white, opaque interlayer from Solutia and then another piece of glass.
“That assembly gave the strength, depth, whiteness and pattern like no other,” says Shannon. “I have a stack probably 3-feet high of rejected ones—different interlayers, trying to do this with frit only, different mineral free glass, etc., and this was the recipe that worked.”
Lite by Lite
“The job was put out for bid about three years ago and was obviously not a standard type of curtainwall systems,” says Juan Speck, president of Sota. “It was a very custom project because we were re-cladding the existing spandrel areas. We provided the engineering, fabrication and installation of the custom curtainwall system. We designed a custom self-locking anchor that was initially bolted to steel structure and frame clipped onto anchors. We also pre-glazed all glass.”
Because of the size of the glass Sota also created custom shipping racks.
“Because the panels were so big we had to have stable shipping steel racks (that fit three frames per rack),” says Speck. “The frames hooked to a trolley systems and that’s what moved them around the building.”
The key to the installation was that it had to happen in a single winter cycle—while the building was fully occupied. A unique system helped make this possible. A three-story rig surrounded the building off of two masts.
“The owner realized from the beginning the re-cladding wasn’t the most difficult part,” says Speck. “The biggest task was to design and deliver an access platform that was safe and efficient and allowed us to work day and night under most weather conditions.”
The final design that was done by Atlantic Hoist and offered the team a three-level system that lowered down the building.
“There were two material hoists on the east and west side, which allowed manpower [to] deliver the tools,” says Speck. “From the working platform, the lower part was used by the demolition crew to remove the marble and the middle and upper parts were used to prepare the building and install the new panels. As you lower down the new panels appeared.”
“Every three days they were able to move the rig down one more floor, working in an enormously productive and effective schedule,” says Shannon. “Brookfield and Ellis Don [the general contractor] were able to visualize, conceptualize and implement this rig and without it this would have gone on and on and on. It was enclosed so installers could work through certain implement weather; it was an amazing assembly. This is a project you couldn’t just build normally.”
In addition to recladding the façade in glass, the building corners were replaced to feature double-laminated glass constructed with a bronze interlayer and full ceramic frit on the #4 surface.
“We were able to respect the importance of that building and its original design … we were able to enhance that with the use of glass, and the pattern and darker corners,” says Shannon, adding that there is also a million square foot podium of retail space in which the stone panels were replaced with the same glass. Ferguson Neudorf based in Beamsville, Ontario, was responsible for the supply and installation of the custom designed, unitized curtainwall system used in the podium portion.
Shannon says he and his firm worked closely with Sota on the project.
“We [architects] work to define the appearance and profiles and required specifications and we have a pretty good idea of what attachments should do, but after that it was really Sota who decided how they wanted that attachment system to work,” he says. “There were a lot of sit-downs with Sota’s team to make sure their execution was consistent with both design and performance goals.”
“The building has a 10-foot module that is defined by the window washing rig that coincides with the column spacing; every 10-feet there is a strong vertical module. And then the vision lites were two 5-foot panels of that bronze insulating glass. From day one we wanted the panels to be 10-feet wide because you can do that with glass, whereas with the stone we had eight panels.”In other words, Shannon explains they were able to transform the scale-reading of the project by reducing the number of panels.
“We worked with installers and manufacturers and they confirmed our feeling that lifting the one panel with the monorail would be far more economical than bringing in two,” he says.
Shannon says while all recladding projects stand on their own in terms of challenge, this one was particularly unique, due to not only the overall scale, but also the fact that they chose to work with fewer lites of glass compared to the number of marble panels originally used. “And it had to be pure white; a lot of white glass buildings either have a gray or green tint. This project is the first time this assembly has been done, that was the greatest challenge.”
For Speck, one of the biggest challenges was being able to work collaboratively with three other trades—in a relatively small space.
“Even though we had a well-designed working platform, it was still crowded with 50-70 workers trying to do their jobs,” says Speck. “So that part was new because there was no escape. We all had to stay and we had to get along and work together. Took a little time to get used to, but once we were all honed in we were able to deliver a floor every three days.”
He adds, “Team work and access to building was the key. We had to find a way to make everyone happy and maintain the project schedule.”
Aside from access to the building and working together, what about the fact that this recladding was being done while the building was still occupied? Speck says it simply wasn’t a major concern.
“It’s important to know the building was only reclad in the spandrel area so the tenants inside were never bothered, as everything was done from the outside,” he says. “If we had changed the ribbon glass that would have been different. But the owner left the windows and replaced only the spandrel. So the only interaction with the tenants was that they could see us as we moved down the building.”
He continues, “We did have to be sensitive to the amount of noise and there was not much except the demo and much of that was done at night when there were fewer people in the building.”
In the end, Speck says the installation and recladding of the tower took a little more than one year.
As on any project, recladding FCP brought along a number of learning experiences and opportunities for the teams involved; all seemed to take away new knowledge and experience.
“I think the one thing we didn’t know was we couldn’t have achieved the project without the rig itself,” says Shannon. “Without the engineering and the elegance of the rig this would not have been possible. It would not have been possible without integration of implementation; the construction technique was fundamental to execution of the design.”
Ellen Rogers is editor of USGlass magazine. She can be reached at firstname.lastname@example.org. Follow her on Twitter @USGlass and like USGlass magazine on Facebook to receive updates.