Completed in 1976, the CN Tower in Toronto, Canada held the record for the tallest freestanding structure in the world from 1975-2007, until it was supplanted by Dubai’s Burj Khalifa. At its highest point, the CN Tower, which is mainly used as a communications and observation tower, reaches 1,815.4 feet (533.33m). Last year, the tower underwent a $16 million renovation and Priestly Demolition shared a fascinating, in-depth video for how they took care of the demolition of the interior space and walls.
Although the top of the tower reaches over 1,800 feet, the observation deck that the project focused on started at the glass floor, which floats 1,136 feet above ground. That height, coupled with the fact that there was still an operating restaurant inside the observation tower, presented some unique challenges to the crews on-site.
The crews only had access to one elevator to haul up all materials haul off debris. Thankfully, the tower is equipped with high speed elevators that travel up to 15 miles per hour, but it still takes almost a full minute to get up to the top floor. Travelling one small trash bin at a time can really add up. Not to mention high winds can slow the elevator down, that’s a lot of time wasted waiting.
Perhaps the most challenging part of the demolition process was removing the existing observation windows to make way for larger glass panels. After the original windows were removed, the leading edge had to be protected for not only worker fall protection, but also to keep materials or tools from falling to the ground below and to protect against the elements, like high winds. A protective fabric material was installed immediately after the windows were removed.
The other major addition to the tower was the installation of a second glass floor, which stands on the floor above the original. In a press release following the completion of the renovation, it was mentioned that the new glass floor could hold roughly 24,700 pounds – or 18 moose (the most Canadian comparison ever). I wonder how much Labatt that equals.
The project is reminiscent of another oddly shaped observation tower, the Seattle Space Needle, which also completed a renovation in 2018. Although not nearly as tall as the CN Tower, the contracting team on the Needle opted to install a 28,000 pound scaffolding ring 400 feet in the air to assist in the demolition and installation process.
Check out the video below from Priestly Demolition for all the details on the demolition process, as well as another nearby project their crews worked on.