We built a 280 sqft rear addition on our 1910 semi-detached in Riverdale. Heritage overlay, mid-block location, neighbours close on both sides. This is the detailed account of the permit process and construction.
The heritage complication: Our street is in a Heritage Conservation District (HCD). This means the City’s Heritage Planning department reviews any addition that is visible from the street or that affects the character of the heritage building. Our rear addition is not visible from the street — the Heritage planner confirmed this in a pre-application meeting and told us we could proceed without heritage approval. This saved us approximately 60-90 days.
Permit application: We used a designer (not an architect — at 280 sqft, an architect was not required). Designer fee: $3,800. We submitted: site plan showing the 7.5m rear setback compliance, foundation plan (strip footing, block on grade), framing plan, four elevations, section, and window/door schedule.
Timeline:
- Submission: September 12
- Zoning review (first): October 3 — they flagged our rear setback calculation as not accounting for an existing bay that extended 0.8m further back than we realized. Revised drawings submitted October 18.
- Permit issued: November 6
55 days total — typical for Toronto.
Construction highlights:
- Demo of the existing small back porch (1970s, non-original): 1 day
- Excavation for strip footing: 1 day
- Footing pour, inspection, and cure: 5 days
- Foundation block and sill plate: 2 days
- Framing: 4 days
- Windows (3 casements): installed same week as framing
- Roofline: tied into the main house with low-slope EPDM roof (the rear of our house already has flat sections)
Cost breakdown:
- Design and permit: $4,600
- Foundation: $8,800
- Framing, sheathing, roofing: $28,400
- Windows: $4,200
- Exterior cladding (brick veneer to match existing): $11,800
- Mechanical extension (in-floor radiant heat off existing boiler): $6,400
- Electrical (2 new circuits): $2,200
- Drywall and finish: $9,600
- Flooring (hardwood to match existing): $4,800
- Total: $80,800
Now serves as a large mudroom/family room transition space off the kitchen. The best renovation we have done to the house.