We bought a Toronto semi with an existing basement apartment that had never been permitted. Previous owner used it as a rental for years. We decided to legalize it properly before renting it ourselves.
What the city requires for a retrofit secondary suite permit in Toronto:
Building permit + zoning review
Minimum ceiling height: 1.95m throughout habitable space (we were at 2.0m — passed)
Egress window in the bedroom (ours was too small — required replacement)
Fire separation: 30-minute fire separation between units (drywall upgrade required in ceiling/shared walls)
Separate smoke and CO detectors in each unit and each bedroom
Kitchen ventilation to exterior
Bathroom exhaust fan to exterior (ours was going to the crawl space — fail)
Fire-separation drywall upgrade (ceiling of basement unit, shared walls): $3,800
Kitchen range hood vented to exterior (new penetration through rim joist): $680
Bathroom exhaust re-routed to exterior: $420
Smoke and CO detectors (4 units): $340
Total work: $9,440 + $1,640 permit = $11,080
Result:
Permit issued, passed all inspections. Unit is now renting at $1,850/month legally. We also added the basement unit to the property’s insurance — monthly premium increase was $43.
Worth it? Absolutely. Legal unit = legal rent, insurance coverage, and the ability to sell the property properly as a legal duplex.
Good decision to do this properly before renting. The unpermitted suite scenario is one of the most common things we see in Toronto semis and detached homes — and the gap between “it’s been renting for years with no issues” and “now there’s an insurance claim or a tenant dispute” is usually just one bad event.
A few things that catch people off-guard in Toronto retrofit suite permits that are worth flagging for anyone reading this thread:
Fire separation is almost always the biggest cost item. Toronto requires a 30-minute fire separation between the suite and the rest of the dwelling. That typically means Type X drywall throughout the ceiling of the basement suite and the floor above it. If you’ve got an older home with plaster, open joists, or wood lathe, you’re usually looking at a full ceiling replacement from below — which is labour-intensive even when it’s straightforward.
Egress windows have a specific opening size requirement. The 2.0m ceiling height that you mentioned — good news you passed. But the egress window is separate: minimum 0.35 m2 opening, and no dimension less than 380 mm. A window that looks big enough often isn’t when you measure the actual openable area. This one surprises people who thought they were in the clear.
The electrical inspection runs concurrent with building, not after. Some contractors sequence the work assuming electrical gets done last. In Toronto, the ESA inspection needs to be coordinated as part of the permit process for the suite, not bolted on at the end.
Smoke and CO alarm placement in the suite has specific room-by-room requirements that go beyond what most existing homes have — smoke in every bedroom, every hallway outside bedrooms, every storey including the common area above.
Sounds like you’ve done the work the right way. The ROI on a legal suite in Toronto is real — but only if it’s done in a way that holds up when it matters.