Scenario 1
Keep the house and add 2 units
Keep the existing house, add a basement or in-house suite and a garden suite.
- Added floor area65–87 m² (700–931 sq ft)
- Units2–3 units incl. the house
- Approval pathAs of right (zoning review and building permit)
- Timeline3–6 months approvals + 6–12 months construction
How we estimated it
- Additional units
- up to 2Property report: second units and garden suites screen
- Second unit
- 65 m²Second unit (basement or in-house) about 65 m² (typical, needs confirmation)
- Rear yard
- 11.7 m deep, 54 m²Existing house about 12 m deep (typical, needs confirmation)
- Garden suite
- 22 m² footprint × 1 storey = 22 m²City of Toronto, garden suites summary: footprint up to the smaller of 40% of the rear yard and 60 m²; 4.0 m high (5 m from the house) or 6.0 m (7.5 m from the house)
- Timeline
- approvals 3–6 months, construction 6–12 monthsApproval and construction months (typical, needs confirmation)
Key risks
- Screen: Estimated lot depth under 30 m: the rear yard may be too short for a garden suite
- Garden and laneway suites need fire access from the street and room for servicing; check both early.
Rough budget and residual land value
Enter your own figure. We could not verify the Altus Group 2026 Canadian Cost Guide ranges (free download at altusgroup.com/featured-insights/canadian-cost-guide); use its range for this building type in your market, or a builder's quote.
Your own estimate of what the finished space sells (or is worth) per sq ft. This public tool does not use MLS® sales data.
Design, permits, consultants, legal, insurance and marketing: commonly 15–25% of hard cost (typical, needs confirmation).
Second and third units are exempt. Rates: City of Toronto DC rates effective June 26, 2025, non-rental (singles and semis $137,846; multiples 2+ bedrooms $113,938; apartments 2+ bedrooms $80,690) · Toronto Catholic DSB education development charge, $3,893 per unit (Dec 3, 2025 to Dec 2, 2026; $4,193 from Dec 3, 2026). The TDSB levies none
Construction loan rate (typical, needs confirmation).
On average about half the cost is drawn over the build (typical).
Builder's margin on revenue: commonly 12–20% (typical, needs confirmation).
Share of gross floor area that is sellable or rentable (walls, stairs and halls excluded).
Enter a hard cost and a sale value per sq ft to see the value added.