From 2015 to 2017, UrbanToronto and its sister publication, SkyriseCities, ran an occasional series of articles under the heading Explainer. Each one took a concept from Urban Planning, Architecture, Construction, or other topics that often wind up in our publications, and presented an in depth look at it. It's time to revisit (and update where necessary) those articles for readers who are unfamiliar with them. While you may already know what some of these terms mean, others may be new to you. We will be (re)publishing Explainer on a weekly basis.

Along with the updated and republished articles, we are also adding to the Explainer series, filling in gaps in the general knowledge bank. This week's article is brand new.

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Residential vs Commercial Floor-Plates: Not All Density is the Same

In Toronto development, size matters when it comes to the floor-plates of new buildings. Based on the City’s experience with building form from over the decades, the Planning Department has developed guidelines that it asks developers to follow, depending upon the type — residential or commercial — and the typology — mid-rise of high-rise — of a building proposal.

Residential

Where residential towers once assumed a large, slab, ‘Y’-shaped, or cruciform appearance of 1,400m² / 15,000 ft² or more, today residential developers are restricted to square (point tower) or rectangular (cereal box) shapes of no more than 750m² / 8,000 ft². These restrictions, which are intended to limit the bulk of buildings when seen from afar, first appeared in 2013 in the Tall Building Guidelines (TBG), a document which strictly-prescripts what Planning is willing to accept in a new condo or apartment proposal. 

The only time a proponent might be allowed larger floor=plates is if the tower is taller than normal, so that the given aspect ratio still looks proportionally correct – MOD Development’s Massey Tower, for example, was approved at 906m² per floor since it reaches over 200m in height.

Commercial

Toronto’s Tall Building Guidelines, however, only apply to residential structures. Office buildings do not need to conform to the TBG stipulations since the City believes that new employment space is valuable enough and new office towers are rare enough to allow them greater latitude for freer expression and larger girth. Indeed, new office tower floorplates typically range between 15-20,000 ft² at the small end, to over 35,000+ ft² at the large end.

Negotiating Massing and Height

A phenomenon familiar to UrbanToronto readers is the practice of negotiating rezoning applications with the City. As the site and context where a proposal is located will differ at least slightly from every other site in the city, the way that the TBG are applied on a particular site is open to interpretation… and therefore, negotiation. If you read last week’s Explainer, you will remember the talk about setbacks, step-backs, and angular planes. At times, Planning will accept additional height in exchange for increased setbacks, step-backs, or other open-space contributions which limit the floor-plate of the tower. Lifetime’s XO2 Residences, for example, was approved at 19-storeys, two more than the initial 17-storey application, since additional space at grade and setbacks to the tower element were secured by the City.

XO2 Condos, as initially proposed at 17 storeys, and as approved at 19 storeys, images courtesy of Lifetime Developments

This sort of negotiation is very rare for office projects as space is valued differently in this building typology. As condo or apartment dwellers spend the majority of their time in a single unit on a single floor, the total number of floors in a project is not of concern to them. Office tenants, by contrast, prefer large, open floor-plates since that way they can better group their employees over fewer floors. This leads to increased cohesiveness, communication, and innovation simply because walking across the floor to a meeting or a colleague’s desk is faster and more pleasant than waiting for an elevator.

A typical office floor at The Well, image courtesy of Allied REIT

A company leasing space across multiple floors in an office tower will have employees commuting between floors regularly, so, for example, if that company is leasing 60,000 ft² they will generally prefer to do so over three floors of 20,000 ft² rather than six of 10,000. It is for this reason that office developers are far more hesitant than their residential counterparts to reduce floor-plates by increasing setbacks or introducing step-backs in exchange for additional floors in their projects.

As mentioned earlier, since every site is unique, exceptions to the rule do, of course, occur. In October, 2021, a settlement was reached with the City for Allied and Westbank’s unusually wide Union Centre, designed by Danish architectural firm Bjarke Ingels Group (BIG). Where the initial plan featured a 91.5m wide by 35.08m deep building (3209.82m² or 35,553.71 ft² floor-plate) which reached 274.18m in height, the final project will span 87m by 35.08m (3,051.96m² or 32,854.34 ft² floor-plate) but will reach a maximum height of 300m. Through mediation with the City, the proponents accepted that maintaining 92% of their initial floor-plate in exchange for the additional height would work; the City would get a building that did not look so outsized on its skyline, while the proponents still get a large floor-plate that businesses like.

Union Centre, as originally proposed, and as approved, image courtesy of Allied REIT

In general, developers desire to secure as much density as possible for any given project, residential or commercial. How that density is ultimately distributed is an important consideration. Where a condo or apartment does not require communication across or between floors, the purpose of an office building is precisely to foster that sort of interaction among employees. It is, therefore, not necessarily in a commercial developer’s best interest to accept a smaller plate in exchange for additional height, keeping office buildings stockier, while residential towers soar higher than ever here.

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Do you have other planning terms that you would like to see featured on Explainer? Share your comments and questions in the comments section below!

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