Hamilton is one of Ontario's strongest markets for basement apartments and second units, helped by its established housing stock and a city that has actively encouraged additional residential units. This guide covers how to get a building permit in Hamilton in 2026 - from second units to additions - plus the process, fees, and local considerations.
Do You Need a Permit in Hamilton?
You need a building permit in Hamilton for any structural, life-safety, or use change: creating a basement apartment, building an addition, removing a load-bearing wall, adding a garden suite, or building a deck more than 600 mm above grade. As a single-tier city, Hamilton handles building, planning, and servicing approvals in-house, which can streamline coordination.
Basement Apartments & Second Units in Hamilton
Additional residential units are permitted across Hamilton, and the city has promoted them as a way to add housing. A legal basement apartment must meet the Ontario Building Code: minimum 1.95 m (6 ft 5 in) ceiling height (underpinning if lower), 45-minute fire separation, compliant egress windows, interconnected smoke and CO alarms, and independent ventilation. Many Hamilton homeowners also add a separate entrance.
Garden Suites & Additions
Detached garden suites are permitted in Hamilton subject to size, height, and setback rules, and are a popular way to add a rental or multigenerational unit. Home additions and second-storey additions are also common - both require full drawings and often structural engineering to tie into the existing structure.
Local Considerations
- Niagara Escarpment: properties on or near the escarpment (parts of Ancaster, Dundas, and Stoney Creek) can carry conservation and development controls
- Heritage: older downtown and neighbourhood properties may require heritage review
- Established housing stock: lower ceilings in older homes often mean underpinning for a legal basement suite
The Hamilton Permit Process & Fees
Applications are submitted through the City of Hamilton's online permit system with OBC-compliant drawings and Schedule 1. Ontario targets a 10-business-day review for houses once a complete application is filed. Hamilton calculates its permit fee based on construction value, typically $300 to $2,000+ for residential work, separate from the BCIN designer fee. See our 2026 cost guide and permit process.
Planning a project in Hamilton?
Call 416-558-9607 or request a free quote. We prepare BCIN-certified drawings and manage the Hamilton submission.