Basement renovation in Toronto in 2026 costs $35–140 per square foot depending on scope. A 600 sqft basic finish runs $21,000–33,000. A legal second suite with separate entrance can reach $180,000. Here’s how to read those numbers.
What drives basement renovation cost in Toronto
Three variables move the needle more than anything else: ceiling height, plumbing configuration, and whether you need a permit for a structural change. Everything else — finishes, flooring, fixtures — is secondary.
Cost per scope in 2026
| Scope | Cost range | What’s included |
|---|---|---|
| Basic open-concept finish | $35–55/sqft | Framing, insulation, drywall, flooring, pot lights, trim, paint. No plumbing. |
| Mid-tier with 3-pc bathroom | $55–80/sqft | Above + bathroom rough-in, vanity, toilet, shower, tile. |
| Legal second suite | $90–140/sqft | Full kitchen, bedroom, bathroom, laundry, egress windows, fire separation, permit. |
| + Separate entrance | +$10,000–30,000 | Side-door or walkout excavation, structural lintel, exterior door, stairs, railing. |
| Underpinning (low ceiling) | +$300–600/linear ft | Required when ceiling is under 1.95m. Bench or traditional underpinning. |
The permit cost nobody tells you about
Toronto Building Permit fees for a basement renovation run $1,200–4,000 depending on the estimated construction value. You also need drawings — an BCIN designer charges $2,500–5,000, a P.Eng stamps structural at $1,500–3,000. Budget $4,000–8,000 for the admin work on a legal suite. Skipping the permit costs more when you sell.
Real project breakdown: 800 sqft legal suite, Etobicoke 2026
- Framing + insulation: $8,500
- Electrical (ESA permit included): $7,200
- Plumbing (2 full baths + kitchen rough-in): $11,400
- Drywall + tape + mud: $5,800
- Flooring (LVP throughout + tile in baths): $9,200
- Kitchen cabinets + countertop: $7,800
- Fixtures + hardware + trim: $6,100
- Separate entrance (side door + stairs): $21,000
- Permit + drawings: $5,400
- Total: $82,400
Monthly rent on this unit in Etobicoke 2026: $2,100–2,400. Payback period under 4 years.
What inflates the quote
Three things add cost that clients don’t always anticipate: asbestos (any home built before 1985 — abatement $2,000–8,000 if found), knob-and-tube wiring (must be removed from enclosed walls, $3,000–6,000), and waterproofing (if you have active water infiltration, interior weeping tile adds $8,000–15,000 before finishing).
How to get an accurate quote
An accurate basement quote requires a walkthrough — no contractor can give you a real number based on square footage alone without seeing ceiling height, existing mechanicals, and access. CNB offers free walkthroughs anywhere in the GTA. Call (437) 217-5519 or fill out the form below.