Toronto is known for its tall buildings and its contrasting low-rise neighborhoods. More recently, we have seen a proliferation of mid-rise buildings along the city's "Avenues." This is despite the many challenges and costs associated with this building typology.

But I think it's pretty clear that a further evolution is also underway. Laneway housing, which is now permitted "as-of-right," is in the early stages of being adopted and built out all across the city. And eventually I think we'll see many of Toronto's laneways evolve into fully fledged residential streets; perhaps not all that dissimilar from what you might find in compact cities like Tokyo.

This is very exciting to me and I think of it as the city gaining a third hierarchy of residential streets. We'd have our major arteries and avenues. We'd have our residential side streets. And then we'd have our compact laneways. Dare I say that maybe some of these laneways could even house non-residential uses such as small-scale offices.

But along with this shift, I think it's time we look at another infill opportunity -- something that planners Blair Scorgie and Sean Hertel are calling "density transition zones." What these zones hope to be is a new middle transition zone between low-rise neighborhoods (where laneway suites are already permitted) and mid-rise avenues. A place where "missing middle" type housing might be built in close proximity to major streets and existing transit. Let's call it a 100-200m zone that sits right behind our avenues.

In my mind this is immediately beneficial for two reasons. The first is obvious. It could be a place for frictionless missing middle housing. Housing that's more dense than a single family home + laneway suite, but less dense than a typical mid-rise building.

The second immediate benefit is that this transition zone could be used to help improve the overall feasibility of mid-rise avenue development. The reality is that there are many blocks along Toronto's avenues where the lot depths are simply too shallow for proper mid-rise buildings. Density transition zones could help with this, which would be not that dissimilar from how "Enhancement Zones" were intended to work (they were never approved).

If this were to happen, I think there would also be a strong case for softening some of the "requirements" in the mid-rise design guidelines. Requirements like the 45 degree angular plane that new buildings generally need to conform to. All of this would only help the overall feasibility of more European-scaled developments along Toronto's avenues and, in my opinion, that would be a great thing.

But for the same reasons that Enhancement Zones were highly contentious, I would expect a lot of grouchy people and a lot of pushback on this idea. There will be concerns about encroaching on our single-family neighborhoods, and there will be the usual objections that come up with any new development (density, traffic, dog poo, etc.) But if we're serious about building more missing middle housing, we are going to need to find ways to remove the barriers to entry. This scale of housing is simply too small to support a great deal of friction.

To learn more about how density transition zones might work, I would encourage you to check out the great site that Blair and Sean have put together, over here.

Image: Density Transition Zones

I’ve written a lot about mid-rise development on this blog and elsewhere. 

I recently wrote this post responding to a tweet by the Chief Planner of Toronto. And towards the end of last year, I wrote a longer piece for developer Urban Capital’s annual magazine. If you missed it, you should definitely download a copy. Not so much for my article, but because, overall, the UC magazines are excellent. (Credit to David Wex.)

Today, I’d like to focus on one specific “performance standard” from Toronto’s mid-rise guidelines that I’ve been thinking about lately. But more specifically, I’d like to focus on a performance standard that was initially contemplated but never actually got adopted. 

(I apologize in advance if this post gets a bit too geeky for some of you. It refers to a specific land use policy in Toronto, but it has much broader relevance.)

If you take a look at the final Avenue & Mid-Rise Buildings Study and turn to page 56, you’ll see that Performance Standard #5B (Rear Transition to Neighbourhoods: Shallow Properties) was stricken from the report. It was never adopted as a standard.

So what is this all about?

This performance standard had to do with something called “Enhancement Zones”, which was proposed as a way to deal with shallow parcels of land on Toronto’s main avenues. You see, because of the other performance standards – namely the angular plane (see images below) – the depth of an avenue site is hugely important for determining what can ultimately be built on it.

From the city’s perspective, this is a double edged sword. In the case of exceptionally deep lots, you can actually meet all of the performance standards while at the same time exceeding the recommended densities. But in the case of shallow lots, the performance standards sometimes/often make it so that you can’t even achieve the recommended densities. In fact, a lot of sites simply become un-developable.

To give you a visual for what I’m talking about, here’s a section drawing from a zoning by-law that was adopted by City Council for St. Clair Avenue West in midtown:

Here you can quickly see that if you were dealing with a shallow lot of, say, 25m in depth, you wouldn’t have much left over after taking into account the rear property line setback (7.5m above), the front property line setback, and the 45 degree angular plane. Now you’re beginning to see why I said that it is easier said than done to play creatively within the guidelines envelope (thick black line above). When you look at the feasibility of these projects, you quickly end up getting pushed right up against the glass.

But this is where Enhancement Zones comes in. 

The idea here is that an adjacent low-rise residential property (or pair of properties in the case of attached houses) could be included in mid-rise development proposals to create a deeper site that then meets the requisite separation distances between the mid-rise scale and the low-rise scale. To be clear, nothing would be built in the Enhancement Zones. They would just help to relieve some of the setback pressures from the original shallow lot and maybe even create a rear laneway system where one did not exist before.

Below is a drawing from the Mid-Rise Buildings Study showing that new condition. The same 7.5m setback applies at the rear, but now it sits within an Enhancement Zone – formerly an adjacent and separate property. All the text is crossed out because, again, this standard was not adopted.

From a mid-rise development and feasibility standpoint, this makes a lot of sense. Sites that may have been un-developable before, now become developable. This makes it easier for us to achieve the European-scaled mid-rise vision that Toronto has for its avenues.

But for reasons that I am sure you can guess, there are concerns with this performance standard. Probably the most obvious is that, to a certain extent, it destabilizes “neighbourhoods.” And they are intended to be completely stable entities that see little to no intensification. As soon as you allow this to happen, properties sitting in Enhancement Zones would become the prey of developers.

However, there are counter arguments you could make. The owners of these properties would likely receive offers above market value. So maybe they end up better off. At the same time, you could also argue that the more development we unlock outside of “neighbourhoods”, the more stable they can actually remain.

In any event, I’ve been thinking about this lately and I thought it would be interesting to debate the pros and cons of these magical-sounding Enhancement Zones. For those of you inclined to engage in geeky planning discussions, I’d love to hear from you in the comments.