ReHousing the Yellowbelt: Rezoning Single-Family Homes as Multiplex Housing

This innovative research explores the conversion of single-family homes into multiplexes with up to 5 units per lot, creating affordable, high-quality and well-designed housing. The ReHousing research team took an unconventional approach to achieve this. To help influence Toronto’s regulatory reform, they prioritized affordable design and construction, and communicating complex new rules in a straightforward way for citizen developers.

Project scope and expected outcomes

ReHousing the Yellowbelt is an innovative initiative launched in response to the City of Toronto’s Planning and Development department's zoning changes in May 2023. These changes now permit the development of multiplexes — low-rise buildings with 2 to 5 units in a single structure — in all residential neighbourhoods.

Historically, zoning regulations have limited the development of multi-unit housing in residential areas. But these new zoning changes are breaking those barriers and will enable a more balanced housing supply in Toronto.

Transforming Toronto’s housing landscape

The research for this project began in 2022 as a collaboration between the University of Toronto’s architecture faculty, Tuf Lab and LGA Architectural Partners — together forming the ReHousing team. The research team’s main objective was to discover the best ways to promote the development of multi-unit housing in residential neighbourhoods.

For this type of project, policy development typically happens in the early stages with implementation occurring after. The ReHousing team opted for a different approach to ensure uptake and success. They prioritized the creation of the necessary tools to support the policy change before turning attention to regulatory reform.

To start, ReHousing conducted comprehensive research into several areas including:

• changes in zoning and building codes
• different development scenarios
• designs for transforming single-family homes into multi-unit housing

To ensure more equitable impact, the team also partnered with non-profits who have experience converting single-detached dwellings into multiplexes:

• Circle Community Land Trust
• Future Builds
• Partna

The project combines structured design research methods with practice-based knowledge to propose a regulatory framework that encourages the development of multiplexes.

During their research, ReHousing consulted a diverse group of stakeholders, including:

• engineers
• industry partners
• code consultants
• equity advocates
• city agencies

Mobilizing “citizen developers” for a more balanced housing supply

While the new zoning changes make multiplexes legal, achieving a balanced housing supply also requires the development of new units. Through their analysis, the ReHousing team determined that non-professional housing developers, non-profits and start ups play a critical role in creating new units.

As a result, ReHousing focuses on empowering non-professional housing creators, or "citizen developers" to create new units. ReHousing also prioritizes making its resources accessible to new homebuilders who may have been excluded in the past due to racial or economic barriers.

To support these individuals, ReHousing launched ReHousing.ca, a user-friendly, accessible website offering free multiplex designs, explanatory diagrams and informative text. The platform is regularly updated to serve as a comprehensive guide for non-professionals to access the feasibility of creating multiplexes.

Expanding reach, expanding impact

The ReHousing team is making their work widely available through several channels:

• Digital engagement: The team actively connects with the community through popular social media platforms. This not only allows them to share updates and insights about the project, but also encourages discussions and feedback.
• Outreach event: In partnership with the University of Toronto’s School of Cities, the team has organized an outreach event. This interactive session serves as a platform for user-testing, where participants can experience the housing solution.
• Educational video series: To supplement their outreach efforts, the team will produce a series of explainer videos. These videos will provide a visual guide to the project, making complex concepts easy to understand and facilitating a better and broader understanding of the project.

Outcomes and project status

The outcome of this research is a comprehensive regulatory framework and a design catalogue featuring over 50 prototype plans for converting 13 of the most common types of homes into multiplexes.

The ReHousing.ca website is live and continues to evolve into a more comprehensive guide for non-professional developers. The project supports the City of Toronto's efforts towards achieving a balanced housing supply and is expected to intensify low-rise neighbourhoods.