Arthur Avenue North | 04 Unit Conversion
Hamilton
Property Type: Existing 2.5-Storey Single-Family Home
Project Overview:
This project embodies a nuanced, code-informed approach to multi-unit intensification. The owner’s end goal was to convert a traditional single-family house into a legal fourplex consisting of one unit per floor: basement, main, second, and attic. However, the Ontario Building Code imposes more stringent requirements—particularly ceiling height and egress—on buildings with three or more dwelling units. This introduced a major constraint at the outset due to substandard basement height.
Scope & Strategy:
Rather than pursuing variances or costly underpinning, our solution was to phase the approval process:
Phase 1: Apply for a legal duplex conversion focused on the basement and one upper unit. Under Part 9 of the Ontario Building Code, duplexes benefit from more flexible criteria—particularly in relation to basement height (minimum 1.95m or 6'-5").
Phase 2: Once the basement unit is legalized and constructed under the duplex framework, we will initiate a change of use and occupancy permit to expand to four legal units across all levels, using the existing second and attic floors.
By separating the process into distinct, permit-compliant phases, we ensured that the project remained within legal bounds while also setting up future intensification without redundant construction or rework.
Challenges Solved:
Avoided costly underpinning or variance applications by leveraging phased compliance pathways.
Designed internal layouts, exits, and fire separations to meet both duplex and future fourplex requirements from day one.
Planned the servicing, HVAC zoning, and metering to align with a four-unit final state—ensuring a smooth Phase 2 transition.
Investor Benefits:
Immediate rental income unlocked through basement duplex approval while the 4-unit buildout proceeds.
Increased unit count and rental yield without triggering a Part 3 building classification.
Protected capital investment by designing for the final vision while managing short-term compliance limitations.
Current Status:
Duplex permit approved. Four-unit layout pre-coordinated and ready for next-phase submission upon completion of Phase 1 construction.