What Happens If You Buy a Home Without Permits in Ontario
- John Barnhart
- Aug 31
- 4 min read
It’s every homeowner’s worst-case scenario: there’s a knock at the door, and the building department informs you that part of your home — the finished basement, the addition, or the backyard deck — was built without a permit.
Worse yet, they hand you an Order to Comply, requiring you to apply for a permit immediately. Suddenly you’re scrambling to hire a designer, produce drawings, book inspections, and possibly even tear open finished walls or ceilings so inspectors can verify the work.
For many buyers, this shock comes weeks or months after moving in — long after the deal has closed. This happens more often than most people realize, which is why checking for proper permits should be as important as your home inspection or lawyer review when buying a house.
Why Building Permits Matter in Ontario
A building permit isn’t just red tape — it’s your assurance that the work was reviewed for safety and compliance under the Ontario Building Code.
Safety First: Permits ensure structural, plumbing, and HVAC work were properly designed, built, and inspected.
Electrical Work: In Ontario, electrical permits are separate — they’re issued by the Electrical Safety Authority (ESA), not the municipality. Always confirm ESA inspections were done if wiring has been added or changed.
Insurance & Liability: If unpermitted work causes damage (a fire, flood, or collapse), your insurance may not cover it.
Resale Value: When it’s time to sell, buyers’ lawyers should check the municipal file. Missing or “open” permits can delay or derail a sale completely.
The Remediation Reality: Why Unpermitted Renovations in Ontario Cost More
Cleaning up after unpermitted work is almost always more expensive than doing it right the first time. Here’s why:
Destructive Verification
Inspectors can’t sign off on what they can’t see. That often means opening 20–50% of finished surfaces (drywall, ceilings, flooring) to expose framing, insulation, vapour barriers, plumbing, and ventilation.
Engineered Fixes
If structure was altered or a slab/load path is questionable, you may need engineer-designed reinforcement (beams, posts, footings, slab details) and letters of compliance — none of which are cheap.
Tear-Out & Rebuild
If work doesn’t meet code, municipalities can require partial or complete removal and reconstruction to current standards. By the time you demo, redesign, re-permit, and rebuild, you’ve spent multiples of what compliant drawings and a proper permit would have cost.
ESA Catch-Up
Unpermitted electrical work can trigger ESA defect notices and mandatory corrections before you can get a final.
Timeline Pressure
An Order to Comply puts you on a deadline. Rush fees, change orders, and re-inspection cycles add cost and stress fast.
Penalty Fees
In some municipalities — for example, Hamilton — permit fees are doubled when you apply retroactively. That’s on top of drawings, engineering, and potential tear-out costs.
Ontario Building Code Updates and Unpermitted Renovations
The OBC evolves. Even if a renovation was “to code” years ago, a retroactive permit today can expose gaps because current standards typically apply to the work under review. Common upgrade triggers include:
Egress & Safety: Bedroom window sizes/clearances, stair geometry, guards/handrails, smoke/CO alarm requirements (often interconnected).
Energy & Moisture: Insulation values, air/vapour barrier continuity, ventilation/HRV provisions.
Structure: Beam, lintel, and point-load requirements; slab/thickening details; lateral bracing.
Fire & Separation: Fire-resistance between suites, fire-blocking, spatial separation near lot lines.
Result: Even “sturdy” older work may no longer comply, and bringing it up to today’s code can be significant.
Unpermitted Renovations Ontario: Red Flags for Homebuyers
When house-hunting, watch for clues that renovations weren’t permitted:
A new-looking basement, addition, or deck but no record of a permit with the municipality.
Renovations that look fresher than what’s listed on MLS.
Workmanship that seems inconsistent, rushed, or “off.”
Sellers who dodge permit questions or say “you don’t need one for that.”
⚠️ Important: Buyers should have their lawyer request and review the municipal property file to confirm whether permits were issued and properly closed. That step is essential protection before finalizing a purchase.
What Happens If You Discover Unpermitted Renovations in Ontario
If you discover unpermitted work after buying, the municipality may require you to:
Apply for a retroactive building permit (a “permit after the fact”).
Provide full BCIN-stamped drawings of the existing work (and proposed fixes).
Open up finishes so inspectors can verify concealed construction.
Bring in an engineer for structural issues or slabs.
Correct to current OBC where required — which can mean substantial upgrades.
And with an Order to Comply, you’ll be on a firm timeline — adding pressure and cost.
Why Getting a Permit Up Front Matters
Skipping permits to “save time” or fees almost always backfires:
Homes without proper permits are harder to sell.
Insurance claims may be denied.
Municipalities can order non-compliant work to be fixed or removed.
Retroactive permits cost more: tear-outs, engineering, code upgrades, and in some cities, double permit fees.
Permits protect your investment — and your peace of mind.
How The Building Permit Guy Can Help
If you already own a home and discover unpermitted work, or if you’ve built without a permit and now need to get compliant, we can help. Our BCIN-stamped drawings are designed for municipal approval — whether it’s a brand-new project or a retroactive permit situation.
Final Word
Don’t let your dream home turn into a renovation nightmare. Before you buy, make sure your lawyer checks the property file for permit history. And if you’re already facing an Order to Comply, get the right drawings and approvals in place quickly. A permit check today can save you thousands tomorrow.
📞 Contact The Building Permit Guy for retroactive drawings and code-compliant design services.🌐 www.thebuildingpermitguy.ca | ✉ info@thebuildingpermitguy.ca