The Potential of ADUs: Meeting Canadian Cities Where They Are At
Too small for urbanists, too large for NIMBYs, but just right for neighbourhoods
Housing has been the hot button issue in planning and political circles, garnering attention from the political left, right, and everywhere in between. We’ve heard from housing advocates, researchers, and real estate investors alike that exclusionary, restrictive zoning bylaws have been the major barrier to ease our housing woes and that if municipalities would only pivot to allow for more ‘Missing Middle,’ perhaps we’d have a chance at catching up on our building backlog. With the advent of Bill 23 in Ontario, it's clear that supply-side policies are here to stay, and some of them have been right under our noses, or in this case, in our own backyards.
While many municipalities across Canada already allow for Additional Dwelling Units (ADUs) in existing single-detached zoning districts, (as they have been around for a long time in west coast cities, like Vancouver, often in the form of illegal, non-conforming granny suites, basement units, etc.), they are finally being pursued in detached forms by many municipalities across the country (read: Ontario) as a progressive policy innovation. Known as tiny homes, secondary suites, laneway homes, garden suites or backyard cottages, these units have garnered criticism from across the spectrum - as being either not enough, or, more commonly, too much. Some argue that ADUs are too small, too incremental, or too modest to combat the housing affordability crisis, and fixate on increased density as an all-encompassing solution without concern for the political will of many cities. Another perspective takes a Not-In-My-Backyard (NIMBY) position, fearing that these units will substantially alter the character of their neighbourhoods, and lead to concerns around noise and parking.
However, neither of these positions recognizes the compromise that ADUs provide: their ability to proverbially meet neighbourhoods where they are at, while adding a significant amount of new housing to meet individual, as well as collective needs across the country.
Part of their brilliance is their modesty - both in size and in potential impact to the existing built environment - as both attached and detached ADUs fit within neighbourhoods like puzzle pieces that can be specifically crafted to conform to their surroundings. ADUs are typically hidden and cannot be seen from the street view, and if they are visible, they are often garage-like sizes. This confuses the argument from those who wish to preserve neighbourhood character, as height and size restrictions often limit their imposition on the built environment. Additionally, ADU policies arguably give homeowners more power, as they gain the ability to modify their own spaces, that is to say “Yes, in my backyard!” through the creation of rental opportunities and spaces for families and friends that can positively affect their own familial situation. With an aging population and many in need of smaller, single-storey, manageable spaces, ADUs provide an avenue for families to have privacy, yet be close by. This form of development is low impact neighbourhoods in comparison with multi-family mid-rise dwellings for example, and if pursued en masse, these units have the potential for high impact through their alteration of the housing supply.
In Ontario, by allowing an attached/internal unit (i.e. basement suite) in addition to a detached unit (i.e. garden suite) the province has now pushed municipalities to effectively allow for the doubling or tripling of density (and ROI) as of right on individual lots - meaning, if they conform to the zoning bylaws, their neighbours can’t contest these developments. However, municipalities can still effectively limit ADUs through setbacks, lot coverage restrictions, and even onerous and opaque processes to get a building permit. I have heard (and been through!) war stories of property owners trying to go through a minor variance process because they are 2% over the lot coverage requirement and then the neighbour chimes in because they are concerned about parking. Even more, being able to effectively apply these zoning bylaws to residential land has been an initial challenge for the average homeowner, as knowing where you can even build an ADU on your property can be a challenge, to say the least.
To solve this problem, I co-founded ADUSearch to make this information available for homeowners and policymakers alike (new version coming in February 2023!). Funded by CMHC’s Housing Supply Challenge, our research team developed an online tool to estimate the potential for detached ADUs by mapping actual zoning bylaws to see if a minimum size unit would fit in the buildable area of a backyard. Take Windsor, Ontario, a largely suburban mid-sized city of 200,000 people that is now dealing with skyrocketing housing prices. Our initial proof of concept revealed that 29,000 lots, or 43% of residential lots in the city, could potentially house a detached ADU, with at least another 10,000 being potentially eligible with additional considerations (journal article forthcoming!). This number did not even take into account potential additional internal/attached ADUs, as the City of Windsor’s zoning bylaw allowed for both an attached and detached unit in any residential district prior to Bill 23. Recent polling (July 2021) as part of the project revealed that almost a third of homeowners in Ontario would be interested in building an ADU if money and knowledge were not a limiting factor, signaling that a city the size of Windsor could add anywhere from 5,000-10,000 units if the right incentives, education and information on the processes were provided. This example is not unlike many Canadian cities, and with the right incentives and regulations, many municipalities are well-positioned to not only add housing units, but to expand the prospect of development to the average homeowner. Additionally, as developers struggle to make the numbers work to build anything other than luxury condos or market-rate rental units, leveraging existing homeowner equity is a necessary component of our strategy to add supply in short order.
A new version of the tool (that we are releasing next month!) has estimated that in Ontario alone, over 600,000 lots are eligible in the 18 cities we’ve been able to map. That translates to roughly 43% of residential lots being eligible for detached ADUs, and 84% being able to have an internal or attached unit based on their zoning designation and building type (so roughly 1.3 million lots). And this is only having mapped 36% of the province (by population). These results are staggering when you think about Ontario’s housing targets being 1.5 million units in the next decade, and that two thirds of our cities are ‘suburban’ in nature. More to come on this one!
To be clear - ADUs are not the silver bullet to solve the housing crisis. By default, these units are additional or accessory, meaning they cannot be severed and sold, which creates de facto rental units by right in neighbourhoods that are dominated by homeownership. Allowing for ADUs potentially deconcentrates rental housing and opens up opportunities for sought after mixed income living situations. Without a monumental shift away from their suburban character, a change in political will and a massive upheaval of our planning regime, many mid-sized cities like Windsor will not be inclined to, nor be able to, alter established neighbourhoods with predominantly single-family dwellings to create the ‘Missing Middle’ density we are needing en masse in the near future. No, homeowner-led ADU development will not drastically alter exclusionary bylaws in suburban cities across the country, and, yes, it will keep low-density neighbourhoods largely intact; but it will do so while potentially doubling, and in some cases, tripling the density on a per lot basis.
ADUs bypass the need for the politically untenable overhaul of zoning bylaws, while adding to supply when we are struggling to keep pace in Canadian cities. Governments of all levels should be encouraging ADU development and relate those policies back to address environmental concerns (by encouraging gentle densification and limiting sprawl), social needs (multigenerational living options for families), and financial distress (more opportunities to build affordable units that are not monopolized by profit-driven developer interests). When it comes to untapped housing supply that will decentralize and democratize development, ADUs are one of the best policy proposals currently on the table for Canadian cities.
