Quick Answer Box: A 1000 sq ft addition cost in Ontario runs $300,000 to $550,000 in 2026, or roughly $300 to $550 per square foot. Second storey additions land at the higher end of that range, while single-storey rear additions trend lower. Permits, engineering, and finish level shift the final number within that band.
How Much Does a 1,000 Sq Ft Addition Cost in Ontario in 2026?
A 1,000 sq ft addition in Ontario costs $300,000 to $550,000 in 2026, with second storey builds running $375,000 to $550,000 and single-storey rear additions landing closer to $300,000 to $400,000. Toronto and GTA projects push toward the top of every range because of higher labour rates and stricter zoning review.
The cost of a home addition in Ontario scales almost linearly with square footage past the small bump-out range, a relationship covered in more depth in Leedway’s complete Ontario home addition cost guide. Standard finishes keep you near the bottom of each price band. Custom millwork, an ensuite bathroom, or a Toronto postal code pushes you toward the top.
Second Floor Addition Cost vs a Single-Storey Build
A second floor addition cost for 1,000 sq ft typically runs $375,000 to $550,000 at $375 to $550 per square foot, climbing past $600,000 in premium Toronto neighbourhoods. Building up means removing and replacing the existing roof, reinforcing the first-floor framing to carry the new load, and extending HVAC, electrical, and plumbing upward. A licensed structural engineer has to sign off before drawings move forward. That assessment alone runs $1,200 to $4,000.
A single-storey rear or side addition of the same size costs less per square foot, usually $300 to $400, putting the total at $300,000 to $400,000. It skips the structural load calculations a second storey demands, but it needs a new foundation and full roof system of its own. On a typical urban or suburban lot, fitting a 1,000 sq ft footprint addition often runs into the lot coverage and setback limits set out in Ontario’s zoning bylaw framework well before the budget does. Your house extension cost will land toward the upper end of either range if a Committee of Adjustment hearing, structural surprises, or a full kitchen and bathroom get added to the scope.
For a full breakdown of structural costs, permit timelines, and zoning limits specific to building up, see Leedway’s second storey addition cost guide.
Home Reno Costs by Addition Type at 1,000 Sq Ft
Here’s how home reno costs break down at 2026 per-square-foot rates for a full 1,000 sq ft project.
| Addition Type | Cost per Sq Ft (2026) | Total for 1,000 Sq Ft |
|---|---|---|
| Single-storey rear or side | $300-$400 | $300,000-$400,000 |
| Second storey | $375-$550 | $375,000-$550,000 |
| Toronto/GTA premium finish | $600-$750+ | $600,000-$750,000+ |
If you’re weighing an additional extension once this project wraps, the same per-square-foot math scales up or down at any size.
What Add-On Costs and Permits Apply to a 1,000 Sq Ft Addition in Ontario?
Add-on costs for a 1,000 sq ft addition in Ontario typically run 15 to 30 percent above the base construction price once permits, engineering, and contingency get included. Toronto homeowners building at this size should budget $8,000 to $12,000 for the full permit package, plus 10 to 20 percent of project cost for architectural and structural fees.
Leedway’s planning and financial guidance resource walks through how to size a budget like this against your specific property and zoning envelope.
Add-On Costs Beyond Construction
A 1,000 sq ft addition works out to roughly 93 square metres. At the City of Toronto’s 2026 building permit rate of $18.56 per square metre, the core building permit alone runs about $1,700. That figure climbs fast once the rest of the package gets added: an HVAC permit at $270.95, a plumbing permit if the addition includes a bathroom, and a structural engineering review.
Every structural addition in Ontario has to comply with the Ontario Building Code, and most municipalities require stamped drawings before issuing a permit. Toronto’s FASTRACK stream clears additions under 100 square metres that fully comply with zoning in 5 to 10 business days. Push past a height limit or lot coverage cap, though, and standard review stretches to 4 to 12 weeks. A Committee of Adjustment hearing for a non-compliant design adds another 3 to 6 months and roughly $2,200 in application fees, plus $2,000 to $4,000 for a planning consultant. Confirming an HCRA-licensed contractor for the build is one more safeguard worth checking before signing.
How a 1,000 Sq Ft Addition Compares to the Average Sq Ft of House in Ontario
Statistics Canada’s Canadian Housing Statistics Program puts the median above-grade living area of an existing single-detached house in Ontario at 1,520 square feet. A 1,000 sq ft addition adds roughly two-thirds of that median footprint to an existing home.
That scale is exactly why most 1,000 sq ft projects come from a second storey rather than a ground-floor expansion. Few lots in established Ontario neighbourhoods have enough buildable area left to add 1,000 sq ft at grade without tripping a zoning variance.
Frequently Asked Questions
1. How much does it cost to add 1,000 square feet to a house in Ontario?
A 1,000 sq ft addition in Ontario costs $300,000 to $550,000 in 2026. Single-storey rear additions sit near $300,000 to $400,000, while second storey builds run $375,000 to $550,000, with Toronto and GTA projects often exceeding $600,000 once permits and finishes get factored in.
2. Is a second floor addition cheaper than a single-storey 1,000 sq ft extension?
No. A second floor addition cost typically runs $375 to $550 per square foot versus $300 to $400 for a single-storey build, since it requires roof removal, structural reinforcement, and extended mechanical systems. It does, however, preserve yard space that a ground-floor extension would take up.
3. Do I need a permit for a 1,000 sq ft addition in Ontario?
Yes, without exception. Every structural addition in Ontario requires a municipal building permit and must meet the Ontario Building Code. In Toronto, the full permit package, including building, HVAC, and plumbing permits, typically totals $8,000 to $12,000 for a project this size.
4. Is a 1,000 sq ft addition cheaper than moving to a bigger house in Ontario?
Often, yes. Selling and buying a larger home in the GTA typically costs $100,000 to $150,000 in combined transaction fees: land transfer tax, commissions, legal costs, and moving expenses. A well-built 1,000 sq ft addition usually recoups 60 to 80 percent of its cost in added home equity instead.
5. How long does a 1,000 sq ft home addition take to complete in Ontario?
Timelines depend heavily on scope and zoning approvals:
- Permit-compliant designs: 5 to 10 business days through Toronto’s FASTRACK stream
- Standard permit review: 4 to 12 weeks
- Committee of Adjustment hearing: adds 3 to 6 months
- Construction for a project this size: typically 5 to 9 months start to finish
Conclusion
A 1,000 sq ft addition cost in Ontario lands between $300,000 and $550,000 in 2026, with the final figure shaped by whether you build up or out, how your municipality’s zoning rules apply, and the finish level you choose. Leedway Group’s renovation, addition, and garden suite services cover projects like this across the GTA and broader Ontario market, from the first structural assessment through final permit sign-off.
