2.5K 
Day 4 of the Council on Tall Buildings and Urban Habitat/Council on Vertical Urbanism Conference moved from the halls of the Westin Harbour Castle to guided tours across Toronto and Mississauga. The program offered destinations from the PATH system and the CN Tower to major mixed-use communities such as M City, Exchange District Condos, The Well, and many more. UrbanToronto attended several of the tours. Today, we go inside One Delisle, now rising on Yonge Street just north of St Clair.
Developed by Slate Asset Management, One Delisle is designed by Jeanne Gang and her Chicago-based firm Studio Gang. Famous for the rippling Aqua in Chicago, this is Studio Gang's first project in Canada. WZMH Architects is the Architect of Record and Multiplex Construction Canada Ltd. is the builder. The tower is climbing towards 44 storeys and a height of 155m, with substantial completion targeted for April, 2027. The development will bring 371 luxury condominium units to Toronto's Deer Park area.
A pre-tour presentation detailed how the project, unveiled to the public in 2018, initially faced questions from the community about height and local impact. Through 2019, Slate and Studio Gang engaged with residents in a series of meetings. Zoning approval followed in 2020, while the acquisition of a holdout parcel in 2021 allowed the project to connect more directly with Delisle Park. That same year, Slate launched sales, with marketing that ranged from custom project films and a proprietary typeface to NFT artworks linked to each of the eight penthouses.
The design resolves these conditions with a podium that reinforces Yonge Street’s retail frontage, while the tower transitions from a rectilinear base into a circular form through a series of staggered eight-storey, volumetric modules that rotate incrementally as they rise, creating a spiralling profile. The design draws on Toronto’s unique urban form, where the ravine system and multi-nodal structure influenced landscaped terraces.
Balconies became a central driver of the design, reconceived as microclimates inspired by European “strandkorb” shelters. By incorporating wing walls and deeper terraces, Studio Gang aimed to extend their usability into the cooler months, while also using the modules to carry planting up the facade. Families of modules (each expressed as either balconies or curtain wall) tile around the tower in a rotating sequence. Every floor plate is unique, requiring custom structural solutions.
The tour itself began in the basement, where Multiplex staff led attendees through the main electrical room. This space, soon to be handed over to Toronto Hydro, illustrates the logistical complexity of high-rise construction: each electrical panel requires about a year from shop drawings to delivery, meaning the room had to be built around the equipment to precise tolerances.
Moving up to the second floor, the group stepped onto the outdoor amenity terrace that adjoins the indoor pool. Here, it was explained how the curtain wall system was set out, with the second floor establishing the critical base alignment from which every panel above stacks. Even slight deviations at this level would ripple upward across the tower’s rise.
From there, the tour highlighted the complexity of One Delisle’s modular system. The tower is composed of eight families of modules, each with balcony and curtain wall variations, repeated in a pattern every four storeys. While this offers a degree of standardization, the irregular slab edges ensure that no two floors are the same, compounding the demands of both design and construction. The system was fully 3D-modelled before fabrication, delivering components in stages and testing them in a full-scale on-site mock-up before installation began.
Participants toured the fourth level, where framing has been completed for the residential suites. At this stage, demising walls are erected and inspected for firestopping before being closed up and fitted with mechanical and electrical systems. Engineered hardwood flooring, offered as an upgrade package for these units, was among the features discussed as the group gained a sense of suite layouts and scale.
The tour then advanced to the 25th floor, offering a view of higher-level residences and the vantage point overlooking Toronto in every direction.
An overview was provided of the Automatic Climbing System, the hydraulically powered formwork that enables the core to rise floor by floor. Guides demonstrated how the system carries form panels, concrete pumps, and even a hanging staircase that provides worker access between decks. Attendees also learned how exterior panels are 'flown' into place using the crane and hoists, with the largest hoist in North America brought to the site to handle the oversized curtain wall units.
As construction advances toward its peak, these technologies illustrate the extraordinary coordination required to realize Studio Gang’s vision for One Delisle.
UrbanToronto will continue to follow progress on this development, but in the meantime, you can learn more about it from our Database file, linked below. If you'd like, you can join in on the conversation in the associated Project Forum thread or leave a comment in the space provided on this page.
* * *
UrbanToronto's research and data service, UTPro, provides comprehensive data on construction projects in the Greater Golden Horseshoe—from proposal through to completion. Other services include Instant Reports, downloadable snapshots based on location, and a daily subscription newsletter, New Development Insider, that tracks projects from initial application.
