Navigating Ontario Building Code and Zoning Requirements
Detached Additional Dwelling Units (ADUs) are playing an increasingly important role in Ontario’s housing intensification strategies, creating opportunities for additional housing supply, multigenerational living, and flexible residential use within established neighbourhoods. While detached units located on the same lot as an existing home can provide significant benefits, their design introduces a distinct set of technical and regulatory challenges involving zoning requirements, life safety provisions, servicing constraints, site planning considerations, and Ontario Building Code compliance.
This session examines the practical design considerations affecting detached Additional Dwelling Units in Ontario, focusing on both the conversion of existing detached garages and newly constructed detached residential units. It explores how architects and designers assess existing conditions, navigate approval requirements, coordinate servicing and technical systems, and manage the differing design implications associated with existing structures and new construction projects. Participants will gain practical insight into improving compliance, reducing project risks, and delivering successful residential intensification outcomes.
Key Topics Discussed:
Existing building assessment considerations
Change-of-use and conversion requirements
Structural upgrade considerations
Fire separation and life safety requirements
Existing conditions and compliance challenges
Renovation constraints and limitations
Detached ADU design requirements
Spatial planning and unit layout strategies
Building envelope and energy performance considerations
Structural and servicing coordination
Accessibility and occupant requirements
Documentation and permit considerations
Site planning and zoning constraints
Utility servicing and drainage considerations
Municipal approval pathways
Common design failures and lessons learned
2 activities • 1 videos • duration: 1h 18m
President and Lead Designer | House of Three
Lisa Henderson is the President and Lead Designer at House of Three, where she leads the team with a dynamic blend of technical expertise and creative vision. A licensed Architectural Technologist with a Project Management Certificate, BCIN qualifications, and a Property Management Certificate, Lisa brings both depth and versatility to her role. She is a proud member of both the Ontario Building Officials Association (OBOA) and the Association of Architectural Technologists of Ontario (AATO). As the team lead, Lisa oversees every aspect of the design process—from building code analysis to final drawing approvals—ensuring every project meets the highest standards. She is passionate about designing functional, thoughtful housing that serves the needs of both homeowners and investors. Originally from Roslin, Lisa now calls Kingston home, where she has strong family roots. Outside of work, she enjoys traveling, paper crafting, and listening to murder mystery audiobooks—especially those with a great narrator.
