How much does a home addition cost in Toronto?
Toronto addition permits and their declared construction values — rear, side and second-storey additions in one dataset.
The full spread, not an average
| Percentile | Declared value |
|---|---|
| P25 — smaller jobs | $30K |
| Median | $90K |
| P75 — larger jobs | $250K |
| Largest in sample | $130.0M |
878 permits with a declared value, trailing 36 months. Medians and quartiles only — one outlier can't move them.
Why two of these quote differently
- Whether the addition is at grade or a second storey (the latter usually needs the existing structure reinforced).
- Foundation work and how the new roof ties into the old one.
- Servicing capacity — additions often trigger electrical and HVAC upgrades to the whole house.
- Zoning: floor space index and setbacks decide how much you can add before Committee of Adjustment time and cost.
Check it against the record
| Applied | Address | Declared value |
|---|---|---|
| Oct 2026 | 211 CASSANDRA BLVD
Addition of a covered patio roof attached to the existing dwelling. |
$75,000 |
| Oct 2026 | 25 FOREST MANOR RD
Proposal for a one storey rear addition of a 165.2 sq.m multi-purpose room |
$1,000,000 |
| Oct 2026 | 1255 KENNEDY RD
INSTALLATION OF A 50 ft X 60 ft VINYL CLAD MODIFIED FIESTA 50 ft SPAN ALUMINUM FRAME STRUCTURE |
$50,000 |
| Sep 2026 | 69 STEELES AVE E
Legalized existing Addition; Order to comply 25 256643 WNP 00 VI |
$25,000 |
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.
Data: Open Government Licence — Toronto. Recomputed automatically as new
permits land; the figures above are current as of October 05, 2026.
Pricing a project like this?
The numbers above are the market. For your project specifically — your address, your scope — we'll read the comparables, flag the permits you'll need, and check any quote you've been given against real awarded prices.
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