Mizrahi Developments



UrbanToronto | November 10, 2023

Hardhat Tour of The One: Construction Continues on Future ‘Supertall’

The One has made headlines since its initial unveiling in 2015, and the last few weeks have been no different. Amidst a flurry of news articles regarding the project’s future prospects after a receivership announcement, construction at the site of The One in Downtown Toronto has appeared to maintain at a steady pace.


At the end of October 2023, UrbanToronto was invited to The One’s construction site Bloor and Yonge streets for a second hard-hat tour to view some of the project’s latest milestones, unique construction components, and an update from Sam Mizrahi himself. We last toured the building in February 2023, at which point the building was at the 20th-level, so there are a number of significant updates to walk through.


This is the first of two articles from this October site tour: The first will go into details on various technical elements — the crane, the unique poured corners, central core, and underground parking garage — while the second article will take a look into the residential units, mechanical floors, glazing, and an update from Mr Mizrahi in the ground floor retail space. We have previously covered the receivership announcement, and so the focus of these two articles are to provide an objective update on the construction progress.


Exterior Update

On the day of touring, construction crew had just finished pouring the 41st-storey, putting the current height of The One at 148.55m – meaning the building will officially pass ‘skyscraper’ status next week. In addition, glazing was being installed at level 13 (something we will go into detail in the second article).


We began the tour at the southwest corner of the building, in the laneway off Balmuto Street that will provide vehicular access to the underground garage as well as the rear lobby entrance to The One once complete. This is the location of the first of two construction hoists that we used to reach the top of the building: one hoist to take us from ground level to the level 6 staging area, and another from level 6 up the rest of the tower.


According to Jane McGrath, Coordinator at Mizrahi Developments, there are approximately 200 staff on-site at any given day working throughout the building. She reiterated that construction progress has remained consistent over the last few weeks despite the backdrop of the receivership.


Staging Area

The staging area is located on the 6th-floor space that will be the outdoor amenity space upon building completion. While currently full of materials and equipment, this area is planned to incorporate an outdoor pool, lounge area, and various landscaping elements. It is from this level that access to the rest of the tower is provided through the hoist and crane.


Hoist & Crane

When UrbanToronto last toured The One, the hoist on the south side of the building went up to the 13th floor, however it now provides access up to the 30th floor, with internal stairs used to reach the higher levels. The hoist is scheduled to be raised to level 37 by the end of this week.


The crane is also fixed to the south side of the building, and employs a top-climbing design, meaning that it rises with the building throughout construction by simply adding more sections as needed. The crane is raised every six floors – the most-recent increase was this past weekend.


While we will go more in-depth on the views from the current top of The One, it’s clear to see that the views south — even from less than half its future total height — will command impressive vistas over the city.


Concrete Corner Pours

Moving up to the 35th & 36th floors, we were able to look at the newly-poured corners of the building. As McGrath explained, The One requires for its corners to be poured separately, which is unique to this building – most skyscrapers complete the full floor area of each level with each pour.


Here, however, due to the complex exoskeleton loading columns, the corner components of each floor are poured separately, before a crew return to install the thinner steel support column at the corner and pour the next corner component on the floor above.


Moving up to the southwest corner of the 36th floor (above, hi Benito!) corner cut-out, which will be poured six days after the floor below was completed and the corner column is installed. You can see the concrete pour on the level above is slightly different as it is the mechanical floor 37, which has a different floor plate shape – an inset octagon rather than a square like the residential levels.


Central Core

One of The One’s unique design aspects is that due to the exoskeleton that supports the load of the building around the exterior, the interior is free of load bearing columns. While not employed often on buildings around the world due to the engineering gymnastics required and subsequent increased costs, this is an evolution of the design pioneered by the original World Trade Center towers in Manhattan. For those towers, the exterior steel columns were designed to support the bulk of the structure with a single column of beams in the centre. This increased the amount of column-free office space on each floor — a design that was both aesthetically and fiscally attractive in terms of leasable floor area. However, while the World Trade Center towers still had a fairly massive central section of beams in which the elevator banks were located, The One’s internal core is currently an empty shaft running the entire height of the building (see below).


Of course this is where the elevators for the residential units will eventually lay, which you can see the top of in the image above, however it is impressive to look at the centre of a 300m+ skyscraper and not see any structural support systems in place. And due to this design, while regular construction method requires each floor to be connected to the building’s core, for The One each floor is poured around this central shaft and connected to the exterior exoskeleton.


Underground Garage

Our final stop in this article is the underground parking garage. As mentioned above, vehicular access will be from the laneway at the southwest corner of the site, from which a ramp connects four levels of underground parking levels.


The One utilizes a mechanical parking lift system in which two cars can be parked vertically in one spot. In this case one SUV and one sedan can occupy one vertical parking stall. The proposed valet service means that every car — whether it be a resident, hotel guest, or visitor — will have their car valeted, which will streamline the process for parking vehicles.


We walked down two levels of the underground ramp, and while the site appears constrained from the exterior, the vehicle ramp is surprisingly spacious. There is dedicated parking on the second lower level for the ground-floor retail space, however we will return to that in article #2 tomorrow.


The underground levels also include a number of mechanical rooms under construction, as well as a series of support and back-of-house spaces such as a separate Parking Valet Lobby & elevator.


Hardhat Tour of The One: Construction Continues on Future 'Supertall'