Basement Renovations and Legal Basement Suites in Mississauga
Leedway Group renovates basements across Mississauga, Oakville and the GTA, from finished family rooms to legal basement apartments, underpinning and new walkouts. Design, permits and construction are handled under one design-build contract.
Most 800 to 1,200 sq ft basement renovations in the GTA cost $45,000 to $90,000 all-in, and legal secondary suites run $90 to $140+ per square foot.
- Tarion Registered and HCRA Licensed
- Family-owned Ontario builder since 2009
- Design, permits and construction under one contract
- Monthly cost reporting
Basement Services
We fix moisture first, check ceiling height and egress, and confirm what your zoning allows before design, so the finished space is dry, legal and built to last.
Basement Finishing
Framing, insulation, drywall, flooring and lighting to turn a raw basement into living space. Basic finishing typically costs $35 to $55 per sq ft. Basement finishing guide.
Legal Basement Apartments
Self-contained second units built to the Ontario Building Code, the Fire Code and Mississauga zoning, with permits and inspections. Typically $90 to $140+ per sq ft. Legal basement requirements.
Basement Underpinning
Lower the basement floor for more ceiling height. Engineered drawings and a City permit are required; GTA pricing runs about $350 to $550 per linear foot. Underpinning guide.
Separate Entrances and Walkouts
New side entrances and walkouts for a separate suite or more natural light, including excavation, structural openings and permits.
Basement Bathrooms and Kitchens
A bathroom or kitchenette with below-grade plumbing. Mid-range basements with a bathroom typically cost $55 to $75 per sq ft.
Waterproofing and Moisture Control
Moisture problems are fixed before any framing goes up, so your finished basement stays dry and healthy.
What a Basement Renovation Costs
Typical 2026 ranges for the GTA. Your price depends on size, moisture condition, ceiling height and whether you add a bathroom or a second unit.
| Scope | Typical cost |
|---|---|
| Basic finishing | $35 to $55 per sq ft |
| Mid-range with a bathroom | $55 to $75 per sq ft |
| Legal secondary suite | $90 to $140+ per sq ft |
| Typical 800 to 1,200 sq ft project | $45,000 to $90,000 |
| Underpinning | $350 to $550 per linear ft |
Why Renovate Your Basement With Leedway
A basement suite has to satisfy the Building Code, the Fire Code and zoning at the same time. We design it to pass all three, then build it.
- Legal suites designed to the Building Code, Fire Code and zoning
- Permit drawings, applications and inspections handled for you
- Underpinning, walkouts and finishing under one contract
- Monthly cost reporting, so you see every dollar as it is spent
- Tarion Registered and HCRA Licensed builder since 2009
Our Basement Renovation Process
01. Private Consultation
Understanding how you live, your site conditions and what the addition needs to do.
02. Feasibility and Design
Zoning review, conceptual design, scope definition and a budget you can plan around.
03. Planning and Permits
Permit drawings, engineering, consultant coordination and scheduling.
04. Construction and Oversight
Hands-on site management, quality control, inspections and monthly cost reports.
05. Completion and Care
Final walkthrough, orientation and warranty support after you move in.
Basement Renovation FAQs
Basic finishing typically costs $35 to $55 per square foot, a mid-range basement with a bathroom $55 to $75, and a legal secondary suite $90 to $140+. Most 800 to 1,200 sq ft GTA projects land between $45,000 and $90,000 all-in.
Most basement projects need a building permit, especially when you add a bathroom, a bedroom, new walls or a second unit. Purely cosmetic work usually does not. We prepare and submit the permit drawings for you.
A legal basement apartment must meet the Ontario Building Code, the Ontario Fire Code and Mississauga zoning, hold a building permit and pass inspection. Key items include ceiling height, egress windows, fire separation, ventilation and interconnected smoke alarms.
On-site underpinning work usually runs 6 to 12 weeks, after engineered drawings and a City building permit are in place.
Only if it is a legal second unit. An unpermitted basement apartment can create insurance and liability problems. We build suites that meet the rules so you can rent with confidence.
A finished basement adds usable living space without expanding your home’s footprint, and a legal suite can add rental income. Compare a basement apartment with a garden suite.
Areas we serve: Mississauga, Oakville, Burlington, Brampton, Milton, Toronto and across the GTA.
More basement guides: Basement renovation costs · Ontario legal basement building code · Underpinning in Mississauga · Basement finishing guide
Plan Your Basement Renovation With Leedway
Tell us about your basement and what you want it to become. We will check ceiling height, egress and zoning and give you a realistic budget range before any drawings are paid for.
Call 905-736-3559 or send the form.