Detached Accessory Dwelling Units – Who benefits and who pays? (2020)

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This research paper examines Detached Accessory Dwelling Units (DADUs) from an affordability lens, addressing both affordability for renters and whether or not DADUs are affordable to build.

Cities across North America are facing unprecedented challenges related to housing affordability, climate resilience and economic sustainability. In many cities, infill housing policies are being adopted in response to these issues. This research focuses on one particular type of infill housing – Detached Accessory Dwelling Units (DADUs). DADUs, also known as laneway homes, garden suites, or carriage houses, are independent rental units typically built in the backyards of single-detached homes.

Key insights:

  • DADUs offer opportunities for downsizing, age in community, multigenerational living, additional rental income, and adaptable housing across the lifespan, often considered as a form of affordable housing.
  • A policy comparison across nine municipalities in Canada and the United States identifies DADU best practices and common characteristics among municipalities with high DADU uptake.
  • A secondary analysis of Edmonton’s DADU permitting data explores the spatial distribution of DADUs concerning affordability.
  • A survey of DADU owners and prospective builders in Edmonton uncovers barriers to development, excluding tenants from the survey.
  • Policy recommendations from the comparison include reducing regulations for flexibility in DADU size, height, and orientation. This involves eliminating parking minimums, owner occupancy requirements, location restrictions, and contextual regulations tying DADU dimensions to the primary dwelling. Such measures aim to foster a successful DADU market.

Research paper authored by Ashley Salvador, University of Waterloo (November 11, 2020).