If you've discovered unpermitted work on your property - or did work without a required building permit - it's important to legalize it. Unpermitted work can cause problems when selling, refinancing, or insuring your home, and may violate the Ontario Building Code.
Steps to Legalize Unpermitted Work
- Assess the work: Determine what was done without a permit and its current condition
- Contact your municipality: Speak with the building department about their process for retroactive permits
- Hire a BCIN designer: Prepare as-built drawings showing the existing conditions - Ontario Design Studio can help
- Apply for a permit: Submit the as-built drawings with your permit application
- Pass inspections: The building department will inspect the work - you may need to open walls or ceilings for inspection
- Make corrections: Any work not meeting OBC standards must be brought into compliance
Why You Should Legalize Unpermitted Work
It is tempting to leave old work alone, but unpermitted construction creates real, ongoing risk:
- Insurance: an insurer can deny a claim - or void a policy - if damage involves unpermitted work
- Resale: unpermitted work must be disclosed, and buyers, lawyers, and lenders often require it be legalized before closing, which can lower your price or delay the sale
- Enforcement: the municipality can issue a stop-work or remedial order, and the Building Code Act carries significant fines for building without a permit
- Financing: lenders may refuse to refinance or approve a mortgage on a property with an illegal unit
- Safety: concealed electrical, plumbing, or structural work may not meet code, putting occupants at risk
Common Types of Unpermitted Work
The projects we most often legalize include finished basements and basement apartments built without a permit, decks and porches, interior renovations that moved walls, garage conversions, and additions. Electrical and plumbing changes usually need their own approvals (electrical work is governed by the ESA).
What Are As-Built Drawings?
Because the work already exists, legalizing it starts with as-built drawings - measured drawings that document the existing conditions accurately, so the building department can review what was actually built against the Ontario Building Code. We measure the space, prepare the as-built set, and identify anything that needs to be corrected or exposed for inspection.
What It Costs to Legalize
Legalizing typically involves as-built drawing fees, the municipal permit fee, and the cost of any corrective work uncovered during inspection. It is almost always cheaper than the alternative of a denied insurance claim or a failed home sale. See our cost guide, or if a previous application was refused, we can fix and resubmit it.
Ready to get started?
Call 416-558-9607 for a free consultation or request a quote online.
Related Resources
- Permit Rejected? We Can Help
- Do I Need a Permit for My Renovation?
- Building Permit Drawing Cost Guide
Frequently Asked Questions
Can I sell my house with unpermitted work in Ontario?
Technically yes, but unpermitted work must be disclosed to buyers and can significantly impact your home's value, insurance, and sale price. Most real estate lawyers and buyers will request that unpermitted work be legalized before closing.