Short answer: Yes, where zoning allows. Hamilton calls a garden suite a detached additional dwelling unit (D-ADU). It can sit in the rear or interior side yard, needs a building permit, may need a grading plan, and needs its own municipal address (City of Hamilton).
Key takeaways
| Question | Short answer | Source |
|---|---|---|
| Name in the by-law | Detached ADU; Secondary Dwelling Unit in zoning documents | City of Hamilton |
| Location on lot | Rear yard or interior side yard | City of Hamilton |
| Eligibility | Check the interactive zoning map and the SDU section of the by-law | City of Hamilton |
| Grading | Professional grading design for some detached ADUs | City of Hamilton |
| Address | Municipal address required; extra fees | City of Hamilton |
| Non-conforming design | Minor variance | City of Hamilton |
What counts as a detached ADU
Hamilton defines an ADU as a separate self-contained unit on the property of a principal dwelling: within it, added to it, or detached. A detached ADU can be newly built or converted from an existing accessory building, such as a rear-yard garage. A lot can have more than one ADU in some cases, for example a detached ADU plus one on the house's second floor; projects reaching three or more units are reviewed by Building Engineering staff (City of Hamilton).
Checking your lot
- Look up the address on the City's interactive zoning map, then read the secondary/additional dwelling unit regulations for your zone.
- A detached ADU goes in the rear yard or interior side yard. Not every lot fits one because of Building Code and zoning requirements.
- Site-specific rules and conservation authority, heritage or Ministry of Transportation approvals may apply. Contact the Zoning Section to confirm.
We do not quote a city-wide size or setback here. They depend on the zone, and we check them on the survey at feasibility.
Permit steps
- Confirm zoning and any minor variance before design is final.
- Grading and notice. Check whether the residential infill rules need a professional grading design, and follow the Good Neighbour Guide notice for detached ADUs.
- Apply online through my.hamilton.ca and the Customer Portal. Use vector PDFs drawn to scale, meeting Building By-law 15-058.
- Address. Apply for the municipal address and post the unit number.
- Build and inspect.
Source: City of Hamilton — Additional dwelling units. Local context: garden suites in Hamilton.
Related permit guides: Burlington · Oakville · GTA rules comparison.
FAQs
Sources
Disclaimer: Figures cited are market estimates provided for information only and are not a quote. Municipal rules, fees, and programs change — always verify current requirements with your local authority. Modular X provides exact pricing only after a site-specific feasibility review.