A legal basement apartment, permitted and inspected

Typical cost in Toronto and the GTA: $90,000 to $150,000 (Unfinished basement to a legal one-bedroom suite with permits; no underpinning). By level of work: Legalizing a finished basement: $10,000 to $20,000; Straightforward conversion: $50,000 to $80,000; Full conversion: $90,000 to $150,000; Conversion with underpinning: $120,000 to $220,000. Ceiling height moves the price most, because a low basement needs underpinning. After that it is the entrance, the kitchen and bathroom, and whether the basement is already finished. These are typical ranges, before HST, with prices checked in 2026; your estimate is built from your own measurements and choices.

A building permit and a passed final inspection. The City’s secondary suite permit covers an interior alteration that adds a second unit, smaller than the main one, in a detached house, semi or townhouse. The drawings show ceiling heights, exits, fire separation, alarms and plumbing, and the application includes a zoning summary and the City’s Rental Renovation Licence screening form. Electrical work is permitted and inspected separately through the ESA.

Under the Ontario Building Code, a secondary suite needs ceilings of at least 1.95 m, or 1.85 m under beams and ducts. Many older Toronto basements fall short. Sometimes rerouting ducts or reframing a bulkhead is enough. If the slab itself is too high, the floor has to be lowered by underpinning or benching, which needs engineering and its own permit fee.

It needs a safe way out that the Building Code accepts, and most suites get their own exterior door. A side door at grade with a few steps down is the least costly. Where there is no side access, we excavate a walkout with retaining walls, a drain and a landing. Bedrooms without a door to the outside need an egress window with a clear opening of at least 0.35 m² and no dimension under 380 mm.

Usually, yes. We draw what is there, compare it with the Code and apply for the permit. Expect some finishes to be opened: ceilings often come down so rated drywall, typically 15.9 mm Type X, can go up, and alarms get interconnected between the units. Published guides put the added cost at $10,000 to $20,000 over a standard finish, and more where an entrance or egress windows are missing.

No. The Canada Secondary Suite Loan Program announced in 2024 has not opened to applicants. Two programs that are open may apply. CMHC-insured refinancing for secondary suites allows up to 90 per cent of the improved value through approved lenders. The Multigenerational Home Renovation Tax Credit is worth up to $7,500 when the suite lets a senior, or an adult eligible for the disability tax credit, live with a relative.

Published estimates disagree widely, from about $1,200 to $3,500 a month for the GTA, and none is appraisal or CMHC survey data. Rent depends on the street, the size, the ceiling height and the light. Ask a local agent for recent leases nearby before you rely on a number. We price the construction; we do not forecast rent.

Yes. We model the suite in 3D with its rooms, kitchen, bathroom and egress windows, so you can see how the unit works and approve the layout before construction starts.