Legal Basement & 2nd Dwelling Unit Construction in Ontario
Safe. Compliant. Inspected.
Why Choose a Legal Basement?
Adding a legal basement or a second dwelling unit is one of the smartest ways to maximize your home’s potential. In Ontario, properly designed and approved basement apartments not only create extra living space but also provide steady rental income and increase your property’s market value.
At GWC General Contractors, we specialize in building legal basement apartments that fully comply with the Ontario Building Code and your municipality’s zoning requirements. From side entrances and egress windows to fire safety, soundproofing, and modern finishes, every detail is handled with precision and care. We manage permits, inspections, and approvals so you can enjoy a stress-free experience while knowing your investment is safe and secure.
- Generate additional rental income
- Create comfortable space for extended family
- Increase your property’s resale value
- Ensure full compliance with Ontario regulations
Our Proven Process
Consultation & Design
We assess your home and create a design plan that matches your needs.
Permits & Approvals
All paperwork, city applications, and BCIN approvals are handled by our team.
Construction & Inspections
Quality workmanship delivered on time, with all required city inspections.
Final Handover
A safe, modern, fully legal basement apartment ready to use.
FAQ
A legal basement is a secondary dwelling unit (SDU) that complies with local building codes, zoning bylaws, fire safety standards, and other municipal regulations. This typically includes:
- A separate entrance
- Fire-rated walls and ceilings
- Egress windows
- A full kitchen, bathroom, laundry(independent or shared)
- HVAC and electrical compliance
- Building and occupancy permits
Yes. In Ontario, converting a basement into a legal unit requires a building permit from the local municipality. Additional permits may include:
- Plumbing
- Electrical (ESA permit)
- HVAC modifications
- Zoning verification
The full process can take anywhere from 8 to 16 weeks, depending on:
- Permit approval timelines
- Scope of construction
- Inspections and compliance checks
- Material and contractor availability
Costs typically range from $45,000 to $120,000+, based on:
- Size of the basement
- Existing layout and conditions
- Above Grade or Below Grade Entrances
- Electrical Panel Upgrade
- Materials and finishes
- Required upgrades (e.g., fire separation, insulation, HVAC)
Yes. Once a basement is fully legalized and inspected, it can be rented out. It must meet local Property Standards Bylaws, and the landlord is responsible for:
- Ensuring ongoing fire safety
- Maintaining structural soundness
- Registering the unit (where required)
Operating or renting out an illegal unit can result in:
- Fines and penalties from the city
- Forced eviction of tenants
- Insurance refusal in case of a fire
- Orders to bring the unit up to code (costly retrofitting)
Yes. The Ontario Building Code requires a minimum finished ceiling height of 1.95 meters (6 feet 5 inches) over most of the area. In old buildings, 6 feet 1 inches is also allowed.
Not necessarily. A shared HVAC system may be allowed with proper fire dampers.
Start with:
- Zoning check to see if a secondary unit is permitted on your lot
- Hire a designer or architect to prepare compliant drawings
- Apply for a building permit
- Hire a licensed contractor with experience in legal conversions
You can apply for permits and do the work yourself if you're the homeowner, but hiring professionals is highly recommended due to:
- Code complexity
- Safety risks
- Inspection failures
- Delays from rework
To pass, ensure that:
- All permitted work is completed exactly as per approved drawings
- All rough-ins (plumbing, electrical, framing) are inspected before closing up
- Final inspection is requested for occupancy
Features of Our Legal Basement Units
Legal Basement Completed
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- Separate side entrance for privacy
- Properly sized egress windows for safety
- Fire-rated walls and soundproofing
- Upgraded plumbing, electrical, and HVAC
- Kitchens, bathrooms, and living areas designed for comfort
- High-quality finishes that feel like a natural extension of your home