How much does a second suite (basement apartment) cost in Toronto?
Declared values for legalizing or building a second suite in Toronto — the permit-visible cost of adding a legal rental unit.
The full spread, not an average
| Percentile | Declared value |
|---|---|
| P25 — smaller jobs | $20K |
| Median | $40K |
| P75 — larger jobs | $50K |
| Largest in sample | $1.1M |
428 permits with a declared value, trailing 36 months. Medians and quartiles only — one outlier can't move them.
Why two of these quote differently
- Ceiling height and egress: a second exit or enlarged windows is the usual deal-breaker cost.
- Fire separation and interconnected alarms throughout the whole house.
- Underpinning or bench footings when headroom is short — this alone can double the project.
- Separate HVAC, and whether the electrical service needs upsizing.
Check it against the record
| Applied | Address | Declared value |
|---|---|---|
| Aug 2026 | 899 VICTORIA PARK AVE
Proposed second unit in basement |
$26,280 |
| Aug 2026 | 102 NEWCASTLE ST
Proposed basement apartment, below grade entrance, enlargement of window, and basement... |
$40,000 |
| Aug 2026 | 1206 BRIMLEY RD
Interior alterations to create a basement suite with a new basement entrance . |
$48,000 |
| Aug 2026 | 27 HARTLAND RD
Legalize Existing Basement apartment unit |
$10,000 |
Where these numbers come from
Declared construction values on City of Toronto building permits (tier C), trailing
36 months, minimum 12 permits before a guide is published. A declared value is
what the applicant stated the work is worth — it can sit below final hard cost,
which is exactly why GROUND also publishes
awarded contract prices.
Suites created without a permit never appear in this data, so these figures describe the legal path only.
Data: Open Government Licence — Toronto. Recomputed automatically as new
permits land; the figures above are current as of August 18, 2026.
Interior fit-outs · New houses · Underpinning · Laneway & garden suites · Additions · Garages