Our renovation to the CN Tower’s Lower Observation Level is the first major renovation of this level since the CN Tower opened in 1976. Working collaboratively with team lead Boszko & Verity since winning the Design-Build competition together in 2021, we have delivered a completely reimagined interior and exterior experience that takes inspiration from an arboreal canopy and other natural elements — tree branches, rocky surfaces, the reflective surface of water, the ripple of a breeze — to honour the Tower as a monument to Canadian life and ambition.

To undertake a revitalization of this iconic landmark, we were challenged to execute a major logistical feat: create more indoor space within the Lower Observation Level’s existing footprint while working 1,200 feet up in the sky. The renovation saw us hoist up a new four-storey permanent maintenance gantry and attach it to the exterior of the Tower’s uppermost observation level. This was the first time a structure of this kind had been hoisted up on cables from the ground since the CN Tower was completed. We used the new gantry to support the extensive exterior and interior work under extraordinary logistical and climatic conditions.

The brief called for a replacement of the original vertical glazing as well as the legendary glass floor, an expansion of the usable interior floor space, and a reimagining of the exterior observation area. The goal was to update and enhance the visitor experience by introducing more steeply angled glass around the Tower’s perimeter and removing the exterior steel cage that enclosed the outdoor terrace, which partially obstructed views. To achieve these objectives, we custom-designed and installed a new perimeter enclosure system and corresponding glass panes. Because the Tower sways and the floors oscillate along the centre axis, we also designed custom-engineered movement connections to fasten the tailor-made structural mullions. All of the dimensions for the glazing as well as the fibre-glass-concrete benches responded to very stringent site and construction hoisting limitations.

The perimeter of the CN Tower’s Lower Observation Level now houses new panes of sloped structural glass and two “Tilt Zones” that allow people to lean over the city in an unprecedented way, and the exterior observation area is enclosed by the same angled glass with mesh screens across the upper portions.

Our sculptural ceiling design is biophilic and modular, marrying aesthetics and function. Honouring the CN Tower’s radial architecture, the parametrically designed modular ceiling features digitally fabricated fins that extend centripetally, drawing people’s gazes out to the unparalleled views of Toronto. The use of oak-laminated phenolic panels for the fins achieves the desired biophilic effect while the fins themselves provide a clever way of concealing — and accessing — an array of mechanical, life-safety, and AV components in a vertically compressed space. The ceiling’s modularity means that pieces can be removed and reinstalled easily to service the systems it so gracefully hides.

Our design also integrates sophisticated AV elements: a 40-ft-long floor-to-ceiling immersive video wall and two 40 x 3.5 ft panoramic screens; three large-format interactive video displays; interactive screens that feature assistive listening via infrared loops concealed within the floor; holosonic speakers; and satellite speakers that provide even and distributed sound coverage throughout the entire floor area. The video wall is an immersive showcase called the Artmosphere, which screens original works by Canadian and Indigenous artists from across the country.

We worked in close collaboration with an accessibility specialist to design beyond best practices and provide a seamless, inclusive experience that supports a diverse range of visitors. The Tower has received Gold Certification from the Rick Hansen Foundation in recognition of the meaningful level of accessibility it has achieved across its spaces.

Images: doublespace photography, Tom Arban, Mike Davidson