The most common question we hear on basement walkthroughs is the simplest one: what's this going to cost? Here's the honest answer, based on the basements we finish across Toronto and the GTA.
The short version
For a standard basement finish — framing, insulation, drywall, flooring, lighting, trim and paint — most Toronto-area projects land between $45 and $75 per square foot. A typical 700 sq ft basement therefore runs roughly $32,000–$52,000.
Add a bathroom and you'll add $12,000–$20,000. Build a full legal secondary suite with a kitchen, separate entrance and fire separation, and total budgets typically run $80,000–$140,000 depending on the house.
What pushes the number up (or down)
Ceiling height and mechanicals. Low ducts mean bulkheads, custom framing and sometimes rerouting — labour-intensive work that doesn't show up in the finished photos but absolutely shows up in the budget.
Moisture. If there's active water entry, it has to be fixed first. Finishing over a wet basement is the most expensive mistake in renovation, because you pay for the basement twice.
Bathrooms and plumbing. A new basement bathroom usually means breaking concrete for drains. It's routine work for us, but it's a real line item.
Egress and windows. Bedrooms and legal suites need egress-compliant windows. Cutting and installing a larger window opening in a foundation wall typically costs $3,500–$6,000 each.
Finish level. Vinyl plank, pot lights and painted drywall keep budgets lean. Wet bars, tiled showers, built-ins and feature walls move you toward the top of the range.
The legal suite math
A legal basement apartment is the one renovation in Toronto that directly pays you back every month. One-bedroom basement suites across the GTA commonly rent for $1,600–$2,200. Even at the higher build cost, most owners see the suite pay for itself in five to seven years — while adding appraised value immediately.
The catch: legal matters. Egress, ceiling height, fire separation, sound attenuation and proper permits aren't optional, and retrofitting an illegal suite later costs far more than building it right.
How to budget intelligently
- Get an itemized quote, not a single number. You can't manage a budget you can't see.
- Fix water issues first, always.
- Decide on the bathroom early — it drives the plumbing layout.
- Hold a 10% contingency. Older homes keep secrets.
Thinking about your own basement? Request a free, itemized quote and we'll walk the space with you, flag any constraints, and give you real numbers for your actual house — not internet averages.