Building Permits & Zoning Violations in Ontario: What Homeowners Must Know

When Is a Building Permit Required in Ontario?

Under Ontario's Building Code Act, a permit is required to:

• Construct a new building exceeding 10 m² (108 sq ft)
• Add to or alter any building
• Change the use of a building or part of it (e.g., creating a basement apartment)
• Demolish any structure over 10 m²
• Install, extend, or alter plumbing, HVAC, or electrical (in some jurisdictions)
• Build a deck above 600 mm (24 inches) from grade
• Construct a pool with a depth greater than 600 mm

Minor work — painting, flooring, non-structural interior changes, replacing fixtures — generally does not require a permit.

Consequences of Building Without a Permit

• Order to comply: Municipal building official orders you to obtain a permit retroactively or restore to original condition
• Fine: Up to $50,000 for an individual; up to $100,000 per day for continuing offences
• Demolition order: If the work cannot be permitted (e.g., setback violation), you may be ordered to tear it down
• Insurance problems: Insurers may deny claims for losses arising from unpermitted structures
• Disclosure obligation: Sellers must disclose known unpermitted work — failure to do so is fraudulent misrepresentation
• Title problems: Lenders may refuse a mortgage or require permits to be closed before closing

Retroactive Permits

In many cases, unpermitted work can be legalized by obtaining a retroactive (as-built) permit. The process involves:

1. Submitting drawings showing the as-built work to the municipality
2. Building inspector visits to assess whether work meets current Building Code requirements
3. Opening walls or exposing elements if the inspector cannot verify code compliance by visual inspection
4. Obtaining a final inspection and permit sign-off

Zoning By-Law Violations

Even permitted construction can violate zoning by-laws — municipal rules governing land use, setbacks, lot coverage, building height, and permitted uses. Common violations:

• Deck or addition too close to property line (setback violation)
• Accessory structure (shed, garage) exceeding maximum size
• Basement apartment in a zone that doesn't permit secondary suites
• Home-based business that exceeds what is permitted as a "home occupation"

Minor Variance Applications (Committee of Adjustment)

If your existing or proposed structure doesn't comply with a zoning by-law, you can apply to the municipal Committee of Adjustment for a minor variance. The Committee applies the "four tests" from the Planning Act:

• Is the variance minor in nature?
• Is it desirable for the appropriate development of the land?
• Does it maintain the general intent of the zoning by-law?
• Does it maintain the general intent of the Official Plan?

Neighbours are notified and can appear at the Committee hearing to support or oppose the variance.