The Missing Middle and the City of Ottawa R4 Zoning Review

Written by Anna Froehlich

January 6, 2020

The “Missing Middle” is a term that often comes up in discussion around intensification, complete communities, housing choice, and housing affordability. It is used to describe the range of housing types between single-detached houses and large apartment buildings that have seemingly “gone missing” from many cities in the last 60-70 years. This is seen in the growing polarization between tall, high density development, usually characterised by smaller urban units; and dispersed, low density housing, often far from services and transit.

The following graphic by Opticos Design, Inc. illustrates the housing types generally considered part of the “missing middle.”

Credit: Opticos Design, Inc.

These housing forms are traditionally where much of the affordable housing stock of cities has been concentrated, in built form that allows greater density and lower cost than large single-family homes, but in a context that is compatible with traditional low-rise residential neighbourhoods.

A number of recent articles and initiatives by academics, policy research organizations, and municipalities have been written to understand the drivers of this phenomenon, and to propose strategies for encouraging development of missing middle built form.

Earlier this year, as part of our lunch and learn series, I presented an article by Evergreen and the Canadian Urban Institute titled What is the Missing Middle? A Toronto Housing Challenge”. The report dives in to the statistics of the missing middle in a Toronto development context, looking at built form, tenure and location, seeking to understand how the missing middle has effected rental vacancy rates, changes in housing tenure, and rising housing costs.

Some of the key factors contributing to the missing middle include:

  • Development pressures driving up land values and making the missing middle housing types economically undesirable;
  • The jump in construction cost between low rise forms of development and high rise concrete construction, making smaller concrete buildings uneconomical; and,
  • Land use policy (such as municipal Official Plans and Zoning By-Laws) that intentionally or unintentionally limits density and built form across large areas of the City.

The City of Ottawa is very much aware of the issue and has launched a City-wide review of Residential Fourth Density – R4 zoning to “explore zoning changes to enable a wider range of low-rise, multi-unit infill housing in R4-zoned neighbourhoods, while respecting compatibility and context sensitive design.” The stated purpose is to “seek to fill a ‘missing middle’ range of affordable mid-density infill housing suitable to a wide range of household types, incomes and tenures, as directed by the Official Plan.”

The City has put out the following video to explain the issue:

To find out more or to provide feedback on the R4 Review process, visit the following website:

Comments will be accepted until January 31st 2020 and can be directed to

Anna Froehlich

Project Manager

January 6, 2020