Many Canadian cities are changing their bylaws to allow for more gentle density. For example, the City of Toronto now allows up to four units per lot in residential zones. Hamilton allows the conversion of single-family homes into up to four units. On the West Coast, cities like Victoria allows between four and six units per lot. Vancouver also allows up to six units per lot, and that number could be increased to up to eight units for purpose-built rentals.
Why are cities making these changes, and why are they targeting more gentle density?
Such changes came into place in response to the current housing crisis, and as relatively easy and fast way to provide more housing supply that answers to the diverse housing needs. In addition to providing fast supply, such changes also generate less of a carbon footprint by utilizing existing buildings and infrastructure and by using fewer new materials to create more units. Gentle density reduces sprawl, uses urban space more efficiently, and creates more walkable, and connected neighborhoods. In other words, gently densifying neighbourhoods can provide more sustainable communities and can create more inclusive, diverse, and resilient community fabric, all while striking the balance between growth and preservation.
But how often is the opposite happening? How often is a city losing dwelling units due to reno-ductions of small multi-family structures such as duplexes and triplexes, into single-family homes?
To try to answer this, we looked at building permit application data in Toronto, flagging all records where a multi-family residential structure was converted into a structure with fewer dwelling units - for example, a duplex being converted into a single-family home or a triplex being converted into a duplex. Specifically, we first filtered only for residential projects, and then compared two columns; "CURRENT_USE" and "PROPOSED_USE". We also tried to validate our findings by looking at the "DESCRIPTION" column of each filtered record, which describes in varying levels of detail the work being done.
The main limitation with the City of Toronto's building permit data is that the inputs for the "CURRENT_USE" and "PROPOSED_USE" columns are not standardized: i.e. it would appear that permit applicants are able to include whatever information they want when they apply for a building permit, and the data are not classified when being inputted into the database. There are hundreds of unique values in each of these two columns, many pertaining to the same type of use but with different spellings (e.g. "Detached SFD", "Detached-Sfd", "Sfd - Detached", etc.). So it is likely that we are underreporting the true number of reno-ductions, as a result of incorrectly-inputted information and records missed by us during the analysis (we tried our best!). The following results should therefore be thought of as more of an exploratory analysis rather than exact numbers.