Accessory dwelling units (ADU)
The Ontario Homeowner's Guide to Laneway Homes, Garden Suites & Bill 23
...cost of your project.
Construction cost estimates (2025) for ADUs in Toronto GTA
Basement suite: $60,000 - $150,000 (Depends on underpinning/ceiling height).
Modular/prefab garden suite: $250,000 - $350,000 (Installed).
Custom laneway home: $350,000 - $550,000+ (Architectural custom builds in Toronto are premium produ...
