Detached ADU in East York - Design, Permits, Construction

East York's wartime housing stock sits on some of the smallest lots inside the amalgamated city, so the binding constraint here is almost never lot coverage - it is the angular plane measured off the rear property line. We design East York garden suites around that plane first and the floor plan second. City of Toronto by-laws apply; East York's tight lots make the 4 m rear-yard setback and 6 m height cap the binding constraints on most designs.

Compact wartime-housing lots, often 30 ft × 100 ft, where the garden suite footprint is set by angular-plane rules rather than by lot coverage. East York sees 120 cm of snow and -3.8°C winter averages. Ontario's 1.2 m frost-depth requirement governs every footing we pour for detached adu, and the April-November season sets the excavation window.

A detached unit stands clear of the main house, so it carries its own foundation, its own service laterals and its own exit - the three cost centres that separate it from an interior conversion on the same East York lot. We trench services across the yard and pour to 1.2 m before the ground closes; framing, envelope and interior finishing then run through the cold months without holding up occupancy. Detached is the highest per-square-foot form of the four, and also the only one that leaves the existing house untouched - no shared walls, no disruption to the occupants during construction.