Service

Basement Finishing in Toronto & the GTA

Underpinning, in-law suites, and functional lower levels.

Finishing a basement in Toronto often involves underpinning, waterproofing, and a building permit for a legal lower level or in-law suite. Nexon Build adds real, livable square footage below grade across the GTA — dry, bright, and fully to code.

We build finished basements that add real livable square footage — from simple rec rooms to full in-law suites and legal basement apartments with separate entrances.

What's included

—Underpinning and lowering
—Waterproofing and drainage
—Framing, insulation, drywall
—Bathroom rough-in
—In-law suite separation

How it works

01Structural and waterproofing assessment
02Design and permit phase
03Underpinning if required
04Framing and mechanicals
05Finishing

Basement Finishing cost in Toronto

Typical range

$50,000–$160,000

Toronto 2026

A finished basement in Toronto runs about $50,000–$80,000 for a legal apartment when the ceiling height already works. If the basement needs lowering, underpinning adds roughly $70–$150 per square foot ($35K–$85K), which is why height is the single biggest cost factor.

Every project is different — get a free, itemized estimate in under 60 seconds, or see the full Toronto renovation cost guide.

Basement Finishingacross Toronto & the GTA

We deliver basement finishing throughout Toronto and the surrounding Greater Toronto Area, including:

Selected work

Renovation & ExtensionKemano

Renovation & ExtensionCanoe

RenovationTimberline

Full RenovationDavenport

Common questions

How much does it cost to finish a basement in Toronto?+

About $50,000–$80,000 for a legal basement apartment when the ceiling height is adequate. If underpinning is needed to gain height, add roughly $35,000–$85,000 ($70–$150 per square foot).

Do basements require a permit in Toronto?+

Yes. Finished basements and basement apartments require a building permit from the City of Toronto, and legal second suites must meet the Ontario Building Code.

What's the minimum ceiling height for a legal basement apartment?+

1.95 m (about 6'5") over the required areas. Below that you'll need underpinning or benching to gain height before finishing.

What's the difference between underpinning and benching?+

Underpinning extends the foundation downward for a new, lower floor and keeps full floor width. Benching builds an angled concrete ledge inside the existing footing — cheaper and faster, but it eats floor area around the perimeter.

Can you build a legal basement apartment for rental income?+

Yes. We handle the egress windows, fire separation, separate entrance, and permits required for a legal, insurable second suite — the details that make the difference between finished and legal.