Decks
Depends on scopeHamilton requires a permit for any attached deck, and publishes additional area/height/cover triggers for detached decks.
Hamilton, ON
Building permits in Hamilton
Hamilton maintains residential building and renovation guidance together with online building-permit services.
Official sources checked Sep. 28, 2026
Permit rules by project
Pick the project that matches your work. These are starting rules for Hamilton; property-specific zoning, heritage and trade approvals can still apply.
Sheds & accessory buildings
Check size / scopeFor an accessory structure serving a detached, semi-detached or row house, Hamilton publishes a no-building-permit path when it is not more than 15 m², not more than one storey and has no plumbing; larger or otherwise triggered structures require a permit.
Basement renovations
Permit requiredHamilton lists interior alterations including finishing or partially finishing a basement among projects that require a building permit.
Secondary suites & ADUs
Permit requiredHamilton lists internal and detached additional dwelling units among permit-required projects.
Home additions
Permit requiredHamilton lists additions, including enclosing an existing porch, among projects that require a building permit.
Interior alterations
Depends on scopeHamilton requires permits for many interior alterations, while minor millwork, cabinetry and flooring are listed as no-building-permit work. The scope must be classified before a single rule is safe.
Walls / structural work
Permit requiredHamilton lists repairs to structural members and adding or removing walls, beams and lintels among permit-required work.
Pools / hot tubs
Depends on scopeHamilton identifies swimming-pool enclosure fences as permit work.
Garages / carports
Depends on scopeHamilton publishes an accessory-structure exemption up to 15 m² for qualifying detached residential structures; larger, plumbed or otherwise non-qualifying garages/carports require a building permit.
Plumbing / HVAC
Depends on scopeHamilton requires permits for new or relocated plumbing and specified HVAC/duct work, while replacement of a plumbing fixture in the same location and furnace replacement are listed as exemptions.
Fences
No building permitHamilton explicitly lists a fence that does not enclose a pool as work that does not require a building permit; the Fence By-law still applies.
Retaining walls
Confirm with cityHamilton’s current fee schedule includes retaining walls as designated structures, but the City does not publish one residential height-only permit rule that covers every site. Confirm the wall height, location and structural conditions before construction.
Demolition
Depends on scopeHamilton requires demolition permits for structures 10 m² or greater, with a published small detached-accessory-structure exemption that can extend to 15 m² for qualifying residential accessory structures.
Apply or ask Hamilton
Use the municipality’s permit office for current forms, fees, drawings and questions about your property.
Hamilton Building & Renovating support
- Phone
- 905-546-2720
- Hours
- Mon–Fri, 8:30 a.m.–4:30 p.m. (excluding holidays)
Your application route
Residential building and renovation permits ↗Use the residential building page for project requirements and the City’s online portal for applications.
Good to know in Hamilton
- The city identifies inspections as part of the permitted construction process.
- Hamilton lists additions, basement finishing, room relocations, wall additions/removals, structural repairs, new/enlarged openings, and many exterior changes among permit projects.
- For decks, Hamilton distinguishes attached and detached work by size and height; attached decks require a permit, and several detached-deck configurations also do.
- A detached accessory structure over 15 m² that is accessory to a detached, semi-detached or row house requires a building permit; plumbing can trigger a permit at smaller sizes.
Official sources
Use these official links to confirm the current rule for your Hamilton property.
View 6 official sources
Sources checked Sep. 28, 2026. Requirements can change; the municipality makes the final permit decision.
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