Legal Basement Apartments in Durham Region: What Homeowners Need to Know

Thinking about creating a legal basement apartment in Durham Region? Great call. These self-contained units—also known as secondary suites—can boost your home’s value, generate steady income, and help with Ontario’s housing shortage.But before you start picking paint colours, there are a few critical legal and structural requirements to understand—especially across Durham Region, where zoning rules vary from town to town.

Here’s a region-wide overview to help you get started on the right foot—and how Wilworks Renovations can guide the process every step of the way.

To be considered legal, a basement apartment must meet:

• Ontario Building Code standards (structural safety, fire separation, HVAC, etc.)

• Local zoning bylaws (specific to municipalities like Ajax, Whitby, Oshawa, etc.)

• Fire and electrical safety codes

• Permitting and registration requirements (varies by town)

Skirting the rules isn’t just risky—it can lead to fines, forced evictions, or insurance issues if anything ever goes wrong.

Every municipality in Durham Region has its own interpretation of what’s allowed. For example:

• Oshawa requires a minimum lot frontage of 11m and specific parking configurations. Check out more specific information about Oshawa’s requirements here.

• Whitby allows second suites in more zones but may have additional requirements for parking and fire safety upgrades.

• Pickering and Ajax each have their own building permit processes and bylaws you’ll need to follow.

Not sure what rules apply in your area? Wilworks can help you navigate them—we’ve built legal basements across the region.

While local differences exist, here are some province-wide essentials:

Ceiling Height

Living areas must have a ceiling height of at least 1.95m (6’5”).

Egress Windows

Each bedroom needs a properly sized escape window. That means an opening of at least 0.35m² (about 3.77 sq. ft.) with no dimension under 15 inches.

Fire Separation & Smoke Alarms

You’ll need:

• 30-minute fire-rated barriers between units

• Interconnected smoke and CO detectors throughout the home

• Fire-rated doors and, in many cases, fire dampers for shared HVAC ducts

Heating, Ventilation & Natural Light

You can use your main HVAC system, but expect to install fire dampers and ensure even heating. Bedrooms and living areas must also meet minimum natural light requirements.

Basement units sit below grade, which makes waterproofing non-negotiable. Damp conditions, water ingress, or foundation cracks not only risk damaging your investment—they can also violate health and safety standards.

At Wilworks, we often combine legal basement builds with:

• Interior or exterior waterproofing

• French drains or weeping tile systems

• Sump pump installation and backflow protection

We’ve built and renovated legal basements across Durham Region—from design and permits to waterproofing and finishing touches. Whether you’re creating a unit for rental income, multigenerational living, or resale value, we handle:

• Permit drawings and submission

• Coordination with municipal inspectors

• Structural work and egress upgrades

• Waterproofing and drainage solutions

• Full renovation from demo to finishes

We stay up to date on local bylaw changes—so you don’t have to.

Building a legal basement apartment in Durham Region is a smart investment, but it’s not a DIY weekend project. Every city has different rules, and skipping a step can cost you big in the long run.

Let Wilworks Renovations handle the complexity while you focus on the benefits. Contact us today for a free consultation and let’s build it right, the first time.