Permits are the least exciting part of any renovation and the part most likely to cause real problems when handled badly. Here's the plain-language version of how building permits work for Ontario homeowners.
The basic rule
Under the Ontario Building Code, you need a permit for work that affects a building's structure, health and safety systems, or use. Cosmetic work doesn't need one. Municipalities administer the process, so details vary slightly between Toronto, Mississauga, Burlington and other cities — but the principles are consistent province-wide.
Renovations that typically NEED a permit
- Removing or altering any load-bearing wall
- Structural changes: new beams, enlarged openings, underpinning
- Creating a secondary suite (basement apartment)
- New plumbing drains or relocating fixtures to new drain locations
- Additions, dormers, and most decks above a certain height/size
- New or enlarged windows and doors in structural walls
- HVAC system changes like new ductwork for a suite
- Finishing a basement when it includes structural, plumbing or suite work (many municipalities require a permit for basement finishing generally — Toronto does)
Renovations that typically DON'T need a permit
- Painting, trim, and interior decorating
- New flooring
- Cabinet and countertop replacement in the same layout
- Replacing fixtures (toilet, sink, faucet) in the same location
- Re-shingling a roof with the same material
- Popcorn ceiling removal
When in doubt, a quick call to your municipality's building department — or a contractor who works there weekly — settles it in minutes.
What permits cost and how long they take
Most residential renovation permits in the GTA cost a few hundred to a couple thousand dollars, scaled to construction value. Straightforward applications (a beam, a basement) are often issued in 2–4 weeks; complex projects or additions take longer. The bigger cost is usually the drawings: structural changes need drawings, sometimes stamped by an engineer.
What happens if you skip the permit
Honestly? Sometimes nothing — until it isn't nothing. Unpermitted work surfaces at the worst moments: a home sale (buyers' inspectors flag it, deals fall apart or get repriced), an insurance claim (insurers can deny claims related to unpermitted work), or a complaint that triggers an order to open up finished walls for inspection. Retroactive permits cost more than doing it right, and removal orders are the worst case.
A legal note for landlords: an unpermitted basement apartment isn't just a fine risk — it can affect your insurance coverage and your standing in tenant disputes.
How we handle permits for clients
We identify what needs a permit during the quote — in writing — coordinate drawings and engineering where required, submit the application, and schedule inspections so the project never stalls waiting on paperwork. You shouldn't have to learn the building code; that's what you're hiring.
Planning a project and not sure what it triggers? Ask us — we'll tell you straight, before any contract is signed.