Toronto’s housing supply consists of two extremes a downtown core of high-rise condos surrounded by low-rise neighbourhoods of single-family houses. This results in the well-documented “missing middle” problem; a scarcity of modest urban density. But the city, where it is currently much easier to build a house than a duplex, triplex or fourplex, also has a “missing little” problem.

According to Toronto’s zoning by-law, a single detached house can be built to a maximum building depth of 17 metres, whereas a multiplex (defined as a building with up to four dwelling units) is limited to a depth of 14 metres. Side yard setback regulations follow a similarly penalizing pattern. These rules raise an important question: Why are we allowing buildings for one household to be bigger than those for multi-generational households and buildings accommodating several households?

The City of Toronto planning department recently published a draft zoning by-law amendment proposing to allow for multiplexes across residential neighbourhoods. Alongside the objective of actually legalizing this type of housing, the planners identified several regulations in the current zoning by-law that seem fundamentally counter-intuitive. This inspired “ReHousing” — a collaboration between Professor Michael Piper and at the University of Toronto Daniels Faculty of Architecture and Janna Levitt of LGA Architectural Partners, along with project manager Samantha Eby and myself. Based on the overarching principle that multiplexes should, at the very least, be permitted the same building size as a single-detached house, we embarked on a research project to visualize what such buildings could look like and determine how many units (and bedrooms) they can accommodate.

Illustration of the generations of typical Toronto house types.
Illustration of the generations of typical Toronto house types.

We started off similarly as any homebuyer does, by looking at real estate listings and then cataloguing typical lot sizes and house types across Toronto’s neighbourhoods. This helped us identify three distinct generations of single-family housing in the city: the Downtown suburbs built until the 1940s with many lots severed since such that frontages today are quite narrow; the Postwar suburbs built in the 1950s to 1970s on bigger lots with a wide range of garages, additions and split-level house variations; and the Metroburb suburbs built in the 1980s to 2000s defined by much bigger houses on smaller lots and typically with attached garages. As we developed housing options across the generations it became obvious that the Postwar suburbs, with larger lots and relatively small existing houses, have the most potential for gentle density. Census data also suggests many of these neighbourhoods have a higher percentage of empty-nester households and sufficient existing infrastructure to support more housing.

With a range of house types selected, we developed a housing catalogue of strategies to convert these single family houses into multiplexes and produced designs at four scales of intensity: LOW are renovations to subdivide areas within the existing building, MEDIUM are small additions, HIGH are major additions, and the NEW involve demolition of the existing house and new construction of a multiplex. Many properties are also big enough to accommodate a Garden Suite/Laneway House in the rear yard. One of the reasons for comparing renovations and additions is to demonstrate that a lot of housing can be added without the time, cost and carbon emissions necessary for new construction. Tearing down a two-storey house to build a three-storey multiplex is expensive and wasteful, whereas converting an existing house into several units and adding an addition is less disruptive and likely more cost-effective.

One of the house types in the catalogue is the Postwar Bungalow, a single-storey house in a neighbourhood where the current zoning allows new houses up to 9 metres in height. The existing home typically has three bedrooms and a finished basement. In the LOW option, the basement is renovated to create a separate unit with three bedrooms. In the MEDIUM option, the ground floor is subdivided and a Garden Suite is built to create four units with a total of eight bedrooms. In the HIGH option, the basement is divided into two units with dedicated access to outdoor areas, and a side addition is added to create five units with a total of nine bedrooms. Lastly, the NEW option proposes to demolish the existing bungalow and build a fourplex or a stacked/back-to-back townhouse with four units and a total of thirteen bedrooms.

Floor plan of the Postwar Bungalow HIGH option.
Floor plan of the Postwar Bungalow HIGH option.

Some of the designs deliberately have more than four units in the main building, particularly the Postwar types with wider lots, to demonstrate that larger properties can handle more housing. Toronto is proposing to allow a maximum of four units on any lot with no additional permissions for larger lots, whereas Vancouver is proposing to allow four to six units depending on lot frontage. The City of Victoria recently passed zoning reforms to allow up to six units on any lot and up to twelve units on corner lots. Meanwhile, Edmonton has created “small-scale infill development” zoning that focuses on form-based restrictions to building size (height, width, setbacks, etc.) and deletes the maximum number of units. My understanding is that provincial legislation in Ontario also defines any building with five or more units as an apartment building and hence municipalities are tied to this threshold. The concerns of a housing crisis might suggest that allowing more than four units is a good idea, however, given the official plan policy of maintaining “prevailing character” to prevent change within residential neighbourhoods, this is the threshold deemed politically digestible.

Rendering of garage at the back of a Postwar Bungalow
Visualization of the Postwar Bungalow HIGH option.

Visualization of the Postwar Bungalow HIGH option.

Much like the built outcome of the Garden Suites and Laneway Suites reforms already implemented, it is unlikely that legalizing multiplexes will make a meaningful impact on housing affordability under current market and policy conditions. High real estate prices, inflated construction costs and the absence of true economies of scale suggests that multiplexes will at least require market-rate rents to pencil out. This is not a silver bullet solution to the housing crisis, but it is a recipe for adding more diverse housing supply without a significant change to the low-rise character of existing neighbourhoods. Legalizing multiplexes is the next step in moving up along the missing middle spectrum and provides housing that is notably more dignified, sustainable and politically appealing than the status quo of “tall or sprawl” development.

The housing catalogue available at is the first phase of research, demonstrating what could be built if it were legal. The next scope of work will combine design, construction, and pricing knowledge to make multiplexes more predictable and easier to finance.

Conrad Speckert is an intern architect at LGA Architectural Partners in Toronto.

ReHousing is a collaboration led by Professor Michael Piper at the University of Toronto Daniel’s Faculty of Architecture and Janna Levitt of LGA Architectural Partners in Toronto. The project is funded by the Neptis Foundation with a mandate to study the gentle densification potential of Toronto’s residential neighbourhoods.

The post Unlocking the “Missing Little” in Toronto’s Housing Supply appeared first on Azure Magazine.


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