Developments Adjoining Toronto Transit Commission (TTC) Structures

Developments Adjoining Toronto Transit Commission (TTC) Structures

As new developments continue to take place in Toronto, the scarcity of land along major transportation networks continue to be a challenge. Developers often seek properties that are readily accessible by public transportation, located in dense portions of the city, and have the highest potential for return.

Often times, we see new developments primarily high- and low-rise condominiums that are built adjoining major arterial roads such as Yonge, Bloor, Sheppard Avenue , and similar roads that are adjoining some sort of major transportation infrastructure. Developing along these roads will often require additional studies, investigations, and specific design criteria that will determine the impacts on not only what occurs on the surface, but as in this case, TTC subway tunnels below.

The Toronto Transit Commission will review any development proposals located within 60 metres of their structures or rights-of-way in order to determine whether the proposal will have any impact or negative affect with respect to their operations, facilities, structures etc.

When we take a look at the 60-metre buffer set in place per the TTC’s Developer Guide, we can often determine fairly quickly if a specific development will be impacted, especially if it is located directly adjoining the street. TTC subway tunnels are fairly large and are often located within the full road allowance in some cases taking up to 60 feet or 18.3 metres in width.

In cases where a development is located within the 60-metre buffer but perceived to have no impact on the structures mainly because of the distance to TTC infrastructure, this review is fairly brief and does not require an in-depth analysis, often times these are considered Level 1 & 2 Reviews. These reviews will still require a fair amount of paperwork including site drawings, architectural, engineering, and updated survey plans.

However, when the proposed work will have an impact or perceived impact, this will often result in a Level 3 & 4 Review in addition to Level 1 & 2. This review will require a much more in-depth analysis of the proposed work by the various departments of the TTC such as structural, civil, mechanical etc., to ensure that the development will not compromise any TTC structures. These reviews will also require a much more precise survey plan that will clearly indicate the distance of the existing TTC infrastructure below grade, in both, vertical and horizontal perspectives, in relation to the surface and the proposed development.

Surveyors are often consulted for these types of requests as they are very intricate and require a lot of coordination with the TTC’s engineering and operations staff. Surveys in these cases take place usually at midnight during non-revenue hours and require surveyors to enter the structures below grade to map out the subway tunnels, tracks, and mechanical rooms that are part of the infrastructure. Once completed, the survey is provided to the various disciplines involved in order to produce a complete set of drawings for submission.

In conclusion, developments along TTC infrastructure should be carefully analyzed especially when building directly adjoining the structure itself. Many considerations have to be accounted for that are often not required for any other development, and certain factors relating to specialized consultants need to be determined prior to consideration for development.


Amar Loai, O.L.S, O.L.I.P
Director of Operations



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