Home Addition Cost in 2026: Toronto and GTA Prices Per Square Foot (CAD)
GTA construction prices by addition type and size, soft costs, Toronto and Mississauga permit fees, US benchmarks, resale returns and Ontario contract rules.
Most Toronto and GTA home additions cost $350 to $550 per square foot of construction in 2026, before HST, according to Capable Group's GTA calculator, so a 250 square foot rear addition runs about $88,000 to $113,000. A home addition is new, permitted floor area joined to your house: a rear or side extension, a second storey or a room above the garage. To get local prices, start with our home additions services.
All GTA, Toronto and Mississauga figures are in CAD. HomeGuide and Cost vs. Value figures are in USD. All figures were checked on October 18, 2026.
Key takeaways
- GTA additions: $350 to $550 per sq ft of construction, before HST (Capable Group, CAD).
- One-storey rear or side: $350 to $450 per sq ft; second storey on top: $400 to $550 (Capable Group).
- Toronto second storey of 800 to 1,200 sq ft: $280,000 to $600,000 before HST (Senso Design).
- Soft costs: drawings, engineering and permits add 15% to 25% (Capable Group).
- Mississauga permit: $13.96 per square metre for a residential addition, $244 minimum (City of Mississauga, 2026).
- US average: $125 to $250 per sq ft, or $50,000 to $100,000 for a 20 by 20 room (HomeGuide, USD).
How much does a home addition cost per square foot in the GTA?
A GTA home addition costs $350 to $550 per square foot of construction in 2026, before HST and design fees, according to Capable Group. A one-storey rear or side addition runs $350 to $450, a two-storey rear addition $350 to $500, and a second storey built on top $400 to $550. Simple shapes and standard finishes keep you near the low end.
| Size | One-storey rear or side ($350 to $450/sq ft) | Two-storey rear ($350 to $500/sq ft) | Second storey on top ($400 to $550/sq ft) |
|---|---|---|---|
| 150 sq ft | $53,000 to $68,000 | Not listed | Not listed |
| 250 sq ft | $88,000 to $113,000 | $88,000 to $125,000 | $100,000 to $138,000 |
| 400 sq ft | $140,000 to $180,000 | $140,000 to $200,000 | $160,000 to $220,000 |
| 600 sq ft | $210,000 to $270,000 | $210,000 to $300,000 | $240,000 to $330,000 |
| 800 sq ft | Not listed | $280,000 to $400,000 | $320,000 to $440,000 |
Source: Capable Group, Home Addition Cost Calculator (2026).
Other GTA guides land in the same band. General West Contractors puts additions at $300 to $550 per square foot (General West), and RenovationRM puts Toronto and GTA additions at $300 to $600 or more, with most projects budgeting $120,000 to $400,000 or more (RenovationRM). RenovationRM says Mississauga, Vaughan, Markham and Burlington tend to land lower than Toronto proper because of easier site access.
Planning an addition in the GTA? Pro House Maintenance matches you with vetted, licensed and insured contractors who give free fixed-price estimates. Compare home addition quotes in Toronto, addition builders in Mississauga or home additions in Hamilton. To shortlist firms yourself, see the best general contractors in Toronto.
What does each type of home addition cost in Toronto?
In Toronto, a mudroom addition costs $18,000 to $50,000 and a single room addition $70,000 to $220,000, according to DavidReno's 2026 guide. A rear ground-floor extension runs $152,000 to $360,000 and a second storey $200,000 to $780,000 or more. Structure and foundation work drive most of the spread between types.
| Addition type | Typical size | Cost per sq ft | Total range |
|---|---|---|---|
| Mudroom addition | 60 to 120 sq ft | $280 to $420 | $18,000 to $50,000 |
| 3-season sunroom | 150 to 300 sq ft | $200 to $350 | $30,000 to $70,000 |
| 4-season sunroom | 150 to 300 sq ft | $350 to $480 | $55,000 to $145,000 |
| Single room addition | 200 to 400 sq ft | $350 to $550 | $70,000 to $220,000 |
| Rear ground-floor extension | 400 to 600 sq ft | $380 to $600 | $152,000 to $360,000 |
| Garage conversion | 300 to 500 sq ft | $150 to $350 | $45,000 to $175,000 |
| Second-storey addition | 500 to 1,200 sq ft | $400 to $650+ | $200,000 to $780,000+ |
Source: DavidReno, Home Addition Cost Toronto 2026.
Senso Design gives similar Toronto totals: $140,000 to $250,000 for a 400 to 500 square foot room above a garage, $175,000 to $350,000 for a 500 to 700 square foot rear extension, and $280,000 to $600,000 for a second storey (Senso Design). It says the garage footing often needs reinforcing for an above-garage room.
RenovationRM splits second storeys by finish: $312 to $390 per square foot for an unfinished shell and $360 to $450 or more for turnkey (RenovationRM). If you only need flexible space, compare against our basement renovation statistics and garage conversion statistics first.
What do drawings, permits and other soft costs add?
Drawings, engineering and permits add 15% to 25% on top of construction, according to Capable Group. Senso Design lists $15,000 to $35,000 for drawings and engineering, $3,000 to $10,000 for a Toronto permit and a 10% to 15% contingency. HST of 13% applies to the construction value.
| Item | Typical cost | Source |
|---|---|---|
| Drawings, engineering and permits (combined) | 15% to 25% of construction | Capable Group |
| Architectural drawings and structural engineering | $15,000 to $35,000 | Senso Design |
| City of Toronto building permit | $3,000 to $10,000 | Senso Design |
| Committee of Adjustment minor variance | $3,000 to $8,000 (if needed) | Senso Design |
| Contingency | 10% to 15% | Senso Design |
| Contingency on structural additions | 15% to 20% | DavidReno |
| HST | 13% of construction value | Senso Design |
City fees are set by formula. Toronto charges $18.56 per square metre for construction in single-family houses, semis and townhouses in 2026, with a $214.79 minimum fee (City of Toronto). Mississauga charges $13.96 per square metre for a residential addition and $12.25 for an unheated one, and residential permits cost at least $244 (City of Mississauga).
How do US addition prices and resale returns compare?
HomeGuide puts the average US home addition at $125 to $250 per square foot in USD, and a 20 by 20 room addition at $50,000 to $100,000. That is well below GTA rates. Resale returns are modest: a midrange bathroom addition recouped 53% in 2025, per the Cost vs. Value Report.
| Item | Typical price or return | Source |
|---|---|---|
| Room addition, per sq ft | $125 to $250 | HomeGuide |
| 20 by 20 room addition | $50,000 to $100,000 | HomeGuide |
| Bump-out room extension, per sq ft | $85 to $200 | HomeGuide |
| Second-story addition, per sq ft | $200 to $500+ | HomeGuide |
| Sunroom addition, per sq ft | $100 to $350 | HomeGuide |
| Midrange bathroom addition | $60,645, 53% recouped | Cost vs. Value 2025 |
| Midrange primary suite addition | $170,517, 32% recouped | Cost vs. Value 2025 |
| Upscale primary suite addition | $351,613, 18% recouped | Cost vs. Value 2025 |
The resale data covers 119 US markets, so treat it as a direction, not a Toronto appraisal. For the wider data set, including ADU growth, see our home addition statistics. To add a room under the roof instead, see our attic conversion cost guide and attic finishing statistics.
How long does an addition take, and how do you hire for one?
A Toronto second-storey addition takes about 10 to 15 months end to end, says Senso Design: 2 to 3 months of design, 2 to 4 months of permits and 5 to 8 months of building. Hire a general contractor who pulls the permit, carries WSIB and liability cover, and puts the price in a written contract.
- Timeline: Senso Design says a minor variance adds 3 to 6 months, and the roof is typically off for 4 to 8 weeks on a second storey (Senso Design).
- Contract: Ontario says any home renovation contract worth more than $50 must be in writing, and recommends a down payment of no more than 10% (Government of Ontario).
- Estimates: If an estimate is part of the contract, the final price cannot be more than 10% over it unless you agree to new work or a new price (Government of Ontario).
- Permits: Ontario says it is your responsibility to get building permits, so write down who pulls them.
Ask each contractor to split construction, soft costs and its own fee on the quote. A GTA general contractor's fee is typically 15% to 25% of hard costs, per our general contractor cost guide. To compare local firms, see the best general contractors in Mississauga, in Hamilton, in Vaughan, in Oakville in Brampton, in Burlington in Markham in Milton or in Richmond Hill, or start from home additions in Vaughan. Thinking of a separate unit out back? See our garden suite statistics for Toronto permit counts and build costs.
Sources
- Capable Group, Home Addition Cost Calculator: Toronto and GTA Prices (2026)
- DavidReno, Home Addition Cost Toronto 2026
- Senso Design, Home Additions Toronto
- RenovationRM, Home Addition Prices: Real Cost Breakdown Per Sq Ft 2026
- General West Contractors, General Contracting Cost Guide (2026)
- City of Toronto, Building Permit Fees
- City of Mississauga, Schedule B: 2026 Classes of Permits and Fees
- HomeGuide, Home Addition Cost
- Cost vs. Value Report 2025, National Averages
- Government of Ontario, Your rights when starting home renovations or repairs
Frequently Asked Questions
How much does a home addition cost in Toronto?
Capable Group puts most Toronto and GTA additions at $350 to $550 per square foot of construction in 2026, before HST. A one-storey rear or side addition runs $350 to $450 per square foot, so 250 square feet costs about $88,000 to $113,000. A second storey runs $400 to $550 per square foot.
How much does a second-storey addition cost in the GTA?
Senso Design says a second storey on a Toronto bungalow adds roughly 800 to 1,200 square feet and lands between $280,000 and $600,000 before HST. Capable Group puts a second storey at $400 to $550 per square foot, because the house below has to carry the new load.
What does a building permit for an addition cost in Mississauga?
Mississauga's 2026 fee schedule charges $13.96 per square metre of floor area for a residential addition and $12.25 for an unheated one, with a $244 minimum. A 50 square metre (about 540 square foot) addition works out to roughly $698 in permit fees before drawings.
How much extra should I budget beyond construction?
Capable Group says drawings, engineering and permits add 15% to 25% on top of construction. Senso Design lists drawings and engineering at $15,000 to $35,000 and a 10% to 15% contingency. Then add 13% HST on the construction value. A minor variance, if needed, adds $3,000 to $8,000.
Does a home addition pay back at resale?
Only in part, in US data. The 2025 Cost vs. Value Report puts a midrange bathroom addition at $60,645 with 53% recouped and a midrange primary suite addition at $170,517 with 32% recouped. Build an addition for the space you need, not as a resale play.
Is Pro House Maintenance free for home addition quotes?
Yes. Pro House Maintenance is free for homeowners. You describe the addition once, and we match you with vetted local contractors who give free written estimates. You compare the quotes and choose who to hire, with no obligation to book.