What's the size limit for a Toronto garden suite?

Toronto garden suites can be up to 60 square metres (approximately 645 square feet) of gross floor area, though several factors can affect the maximum size permitted on your specific lot.

The City of Toronto approved garden suites in 2022, and the zoning bylaw sets out clear parameters. The 60 sq m gross floor area limit applies to most residential zones, but your suite also cannot exceed 6 metres in height (roughly two storeys). The footprint of the garden suite itself is further constrained by your lot's maximum lot coverage rules — meaning the combined coverage of your main house, any garage, the garden suite, and other structures must stay within the permitted coverage percentage for your zone, which is typically 33–40% depending on your neighbourhood.

Setbacks are another key constraint that can effectively limit your buildable area. Garden suites must generally sit 1.5 metres from rear and side lot lines, and there are specific rules about proximity to the main dwelling as well. On a smaller or irregularly shaped lot, these setback requirements can reduce your practical building envelope significantly — sometimes well below the 60 sq m maximum.

Toronto-Specific Considerations

Your lot's specific zoning, any ravine overlay, tree protection bylaws, or heritage designations can all further restrict what's permitted. Toronto's ravine protection rules in particular can dramatically limit rear yard construction in affected neighbourhoods. Before designing anything, it's worth checking your property's zoning on the City of Toronto's online zoning map or calling Toronto Building at 416-397-5330.

A building permit is required for any garden suite — there's no way around this, and it protects your investment significantly. Permit timelines for garden suites in Toronto are typically in the 6–12 week range, so factor that into your project schedule.

Next Steps

Start by having a registered architect or experienced designer review your specific lot conditions — many Toronto firms now specialize in garden suites and laneway suites and can quickly tell you what's feasible. Costs for a finished garden suite in the GTA typically run $250,000–$400,000+ depending on size, finishes, and site conditions (utility connections, grading, etc.).

You can browse architects, designers, and general contractors experienced with garden suites in the Toronto Construction Network directory to find the right professional for your project.