Home addition cost in Toronto in 2026 runs $400 to $700 per square foot for finished space. A 400 sq ft rear addition typically costs
0,000 to $40,000.
Home addition cost in Toronto typically ranges from $40,000 for a small three-season sunroom up to $800,000+ for a full second-storey addition with multiple bedrooms and a primary ensuite. Most rear additions in 2026 land between $150,000 and $400,000 for the construction work, plus permit, engineering and design fees.
Cost by Addition Type
| Addition type | Cost range | Per sq ft |
|---|---|---|
| Three-season sunroom | $40,000 to $80,000 | $300 to $450 per sq ft |
| Bump-out (50 to 100 sq ft) | $50,000 to $120,000 | $700 to $1,200 per sq ft |
| One-storey rear addition (200 to 400 sq ft) | $150,000 to $350,000 | $500 to $750 per sq ft |
| Two-storey rear addition (400 to 800 sq ft) | $300,000 to $700,000 | $500 to $700 per sq ft |
| Dormer addition (150 to 300 sq ft) | $150,000 to $300,000 | $700 to $1,000 per sq ft |
| Full second-storey addition (800 to 1,200 sq ft) | $400,000 to $800,000 | $450 to $700 per sq ft |
| Garage conversion or above-garage addition | $150,000 to $300,000 | $500 to $700 per sq ft |
Cost by Component
For a typical 400 sq ft one-storey rear addition with a kitchen, breakdown roughly looks like:
- Excavation and disposal: $8,000 to $14,000
- Foundation (concrete footings and walls): $25,000 to $45,000
- Framing, sheathing, roofing: $35,000 to $55,000
- Windows and exterior doors: $8,000 to $20,000
- Exterior cladding (brick, stone, siding): $15,000 to $30,000
- Insulation and air sealing: $5,000 to $10,000
- Plumbing rough-in: $4,000 to $9,000
- Electrical rough-in: $5,000 to $10,000
- HVAC extension or new system: $6,000 to $15,000
- Drywall and trim: $7,000 to $12,000
- Flooring: $4,000 to $10,000
- Kitchen finishes if applicable: $35,000 to $60,000
- Paint, fixtures, hardware: $4,000 to $8,000
- Tie-in to existing home (wall removal, roof tie-in, drywall patch): $8,000 to $20,000
- Project management and overhead: 15 to 25 percent of project cost
Permit, Engineering and Design Costs
- City of Toronto building permit: $4 to $7 per sq ft of new space
- Architectural drawings: $5,000 to $15,000
- Structural engineering: $3,500 to $9,000
- Mechanical engineering (if HVAC redesign): $1,500 to $4,000
- Committee of Adjustment minor variance (if needed): $1,200 to $1,800 plus 12 to 20 weeks of timeline
- Survey: $1,000 to $2,500
Toronto Labour Rates That Drive Cost
Toronto labour rates for major trades in 2026:
- Carpenter: $65 to $90 per hour
- Electrician: $90 to $130 per hour
- Plumber: $95 to $140 per hour
- HVAC technician: $90 to $130 per hour
- Tile setter: $70 to $100 per hour or $12 to $20 per sq ft installed
- Drywaller: $55 to $80 per hour
- Roofer: $80 to $120 per hour
These rates run higher than smaller Ontario markets and roughly match other major Canadian cities. Toronto labour shortages in framing and roofing also push timelines, which has its own cost effect.
How to Reduce Home Addition Cost
- Avoid wet rooms in the addition where possible (no kitchen or bathroom adds)
- Match the existing exterior cladding to skip a custom-match line item
- Stay within zoning to avoid Committee of Adjustment
- Pick mid-range cabinets and finishes; the addition is the wrap, not the show
- Avoid moving the staircase
Reference Sources
For Toronto permit fee details, see the City of Toronto building permits page. For Ontario structural and code requirements, see the Ontario Building Code.
Related Pages
Frequently Asked Questions
How much does a home addition cost per square foot in Toronto?
Toronto home additions cost $400 to $700 per square foot for finished space in 2026. Sunrooms run $300 to $450 per sq ft, second-storey additions $450 to $700, and rear additions with kitchens or bathrooms $500 to $750.
What does the home addition cost include?
Our quotes include excavation, foundation, framing, sheathing, roofing, exterior cladding, windows and doors, insulation, drywall, mechanicals, finishes, paint, fixtures, and tie-in to the existing home. Permits, engineering and Committee of Adjustment fees are separate line items.
Why are second floor additions so expensive?
A second-storey addition removes the existing roof and frames an entirely new floor with all the trades involved: framing, roofing, mechanicals, insulation, drywall, finishes. Foundation reinforcement is sometimes needed, and the open-roof phase requires watertight protection. The entire upper level is also usually an unbroken finished space versus a partial reno.
What are the permit costs for a Toronto home addition?
City of Toronto building permit fees for an addition are $4 to $7 per sq ft of new space for residential, with a minimum fee of around $300. A 500 sq ft addition costs $2,000 to $3,500 in permit fees. Committee of Adjustment is $1,200 to $1,800 if a minor variance is needed.
How much does a structural engineer cost for an addition?
Structural engineering for a Toronto addition runs $3,500 to $9,000 depending on complexity. A simple bump-out is at the low end. A full second-storey or significant foundation work is at the high end. Engineering is required for every addition and is well worth budgeting for.
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