Basements ยท Greater Toronto Area
Legal Basement Apartments in the GTA
A legal second suite turns a basement into a self-contained rental or family apartment. The difference between legal and not is the permit, the fire safety and the inspections.
Scope
What is included.
- Feasibility check against zoning and the Building Code
- Permit drawings and application
- Fire separation and interconnected smoke alarms
- Separate entrance and egress windows
- Kitchen, bathroom and laundry
- Electrical, heating and ventilation for a second unit
Cost
What it costs.
From $72,000
Most projects: $72,000 to $125,000
What moves the price
- Whether a new separate entrance has to be built
- Fire separation and egress window work
- Kitchen and bathroom finish level
Prices are in Canadian dollars before HST, as of October 2026. Every project is confirmed with a written quote after a site visit.
Before you start
What to know.
The rules
Ontario now allows additional residential units on most urban residential lots, but each municipality sets its own registration and zoning details. A second suite must meet the Ontario Building Code and be built under a permit.
What inspectors look for
Fire separation between units, a safe exit, ceiling height, window size, smoke and carbon monoxide alarms, and properly inspected electrical work.
Existing unpermitted suites
An older basement apartment built without a permit can often be legalised. We assess what has to be opened up and corrected.
How we work
One team for every stage.
- AssessWe survey the house as it stands.
- Design and permitsDrawings and approvals before work starts.
- Strip-outWhat is worn out comes off.
- RebuildStructure, wiring, plumbing and walls.
- FinishesCabinetry, tile, floors and paint.
- HandoverWalkthrough and documents.
Questions
Legal Basement Apartment: the short answers.
- How much does legal basement apartment cost?
- With Zigma Group, legal basement apartment starts from $72,000, and most projects fall between $72,000 and $125,000. Prices are in Canadian dollars before HST, as of October 2026, and are confirmed after a site visit. The main factors are whether a new separate entrance has to be built; fire separation and egress window work; and kitchen and bathroom finish level.
- What makes a basement apartment legal in Ontario?
- It is permitted by local zoning, built under a building permit, meets Ontario Building Code requirements for fire separation, exits, ceiling height and ventilation, passes inspection, and is registered where the municipality requires it.
- Can my existing basement apartment be legalised?
- Often, yes. We compare it with the current requirements, prepare drawings, apply for the permit and carry out the corrections, which commonly involve fire separation, egress and electrical work.
- Does a basement apartment need a separate entrance?
- It needs a safe means of exit that meets the Building Code. In many houses that means a separate side or rear entrance, sometimes with a new below-grade stair. We work out the best route for your house.
Book a consultation
Tell us what you want to change.
Call or email and we will arrange a visit. We work across the Greater Toronto Area and have been renovating and building homes since 2006.