Do I Need a Building Permit?
Quick reference guide for common residential projects in Ontario. Find out what requires a permit and what's typically exempt.
The General Rule
In Ontario, most construction work requires a building permit. This includes new construction, additions, alterations, and even some repairs. When in doubt, contact your local building department before starting work.
Remember: Even if a building permit isn't required, you may still need to follow zoning bylaws, obtain other permits (electrical, plumbing), or meet setback requirements.
How to Read This Guide
Decks & Porches
Deck attached to house
Almost always requires a permit regardless of size
Deck over 24 inches (60cm) above grade
Height triggers permit requirement
Deck under 24 inches, detached from house
May be exempt - check with your municipality
Covered porch or deck with roof
Roof structure always requires permit
Replacing deck boards only (no structural changes)
Maintenance/repair typically exempt
Sheds & Garages
Shed under 10 sq m (108 sq ft)
Often exempt, but zoning setbacks still apply
Shed over 10 sq m (108 sq ft)
Size triggers permit requirement
Detached garage
Always requires permit
Attached garage
Connection to house requires permit
Converting garage to living space
Change of use always requires permit
Fences & Landscaping
Fence under 2m (6.5ft) in backyard
Typically exempt, but check local bylaws
Fence in front yard
Height restrictions vary by municipality
Retaining wall under 1m (3.3ft)
Usually exempt
Retaining wall over 1m (3.3ft)
Structural concern triggers permit
Pool fence/enclosure
Safety requirement - always needs permit
Pools & Hot Tubs
In-ground pool
Always requires permit plus fence/enclosure
Above-ground pool (permanent)
Requires permit and safety enclosure
Hot tub / spa
Electrical permit usually required
Pool deck
Same rules as regular decks apply
Interior Renovations
Finishing a basement
Creating living space requires permit
Basement apartment / secondary suite
Change of use + fire safety requirements
Removing load-bearing wall
Structural changes always need permit
Removing non-load-bearing wall
May need permit if electrical/plumbing affected
Kitchen/bathroom renovation (cosmetic)
Cabinets, counters, flooring typically exempt
Moving plumbing fixtures
Plumbing permit required
New electrical panel or circuits
Electrical permit required
HVAC & Mechanical
New furnace (same type replacement)
Permit required even for like-for-like
New air conditioner
Permit typically required
New water heater
Permit required
Fireplace or wood stove
Fire safety requirements apply
Ductwork modifications
Major changes may require permit
Additions & Extensions
Room addition
Always requires permit
Sunroom / four-season room
Enclosed space requires permit
Dormer addition
Structural change requires permit
Second storey addition
Major structural work
What Happens If You Build Without a Permit?
Building without a required permit in Ontario can result in:
- •Stop work orders - Your project can be halted immediately
- •Fines - Up to $50,000 for individuals, $100,000 for corporations per day
- •Required demolition - You may have to tear down unpermitted work
- •Insurance issues - Claims may be denied for unpermitted work
- •Sale complications - Title searches reveal open permits/violations
Ready to Apply for a Permit?
If your project requires a permit, here's what you'll typically need:
Contact Your Building Department
Requirements vary by municipality. Contact your local building department for specific requirements:
Related Resources
Have Your Documents Ready?
Our pre-check tool validates your permit package against common rejection reasons before you submit. Free to try.
Run Free Pre-CheckThis guide is for general information only and reflects typical requirements as of December 2025. Requirements vary by municipality and project specifics. Always verify with your local building department before starting work.