🏡 Are Basement Apartments Legal in Markham, Ontario?

What Homeowners and Buyers Need to Know Expert Insight from Markham’s Top Realtor

Meet Michael John Lau Markham’s Top Realtor and Trusted Real Estate Expert
Michael John Lau is recognized as the Top Realtor in Markham, Ontario, and a leading agent at Kaizen Real Estate. Known for his proven success, client dedication, and unmatched local market expertise, Michael helps buyers and sellers find their perfect homes across Markham, Unionville, Cornell, Wismer, Greensborough, and surrounding communities.
For trusted real estate advice, visit www.callmikelau.com.

✅ Are Basement Apartments Legal in Markham, Ontario?

Yes basement apartments can be legal in Markham, Ontario, but only if they meet strict requirements under the Ontario Building Code, City of Markham zoning rules, and Fire Code.

Markham does not automatically consider all basement apartments legal.
A “legal” basement apartment also called a secondary suite or accessory dwelling unit (ADU) must be properly built, inspected, and approved by the City.

If a basement unit has not gone through the proper permitting and inspection process, it is considered illegal, even if it is fully finished or currently rented.

🏠 What Makes a Basement Apartment Legal in Markham?

To be legal, a basement apartment must meet the following criteria:

✅ 1. Proper Building Permit

The construction of the basement apartment must have been approved through a City of Markham building permit.
This ensures:

• Structural safety

• Correct plumbing

• Proper electrical installation

• Adequate ventilation

Without a permit, the unit is not legal, even if it looks fully finished.

✅ 2. Fire Separation & Safety Requirements

Basement apartments must meet Ontario Fire Code standards, including:

• Proper fire-rated walls and ceilings

• Safe, interconnected smoke alarms

• Fire separation between the main unit and basement unit

• A fire-rated mechanical room

Many older Markham homes do not meet these requirements without upgrades.

✅ 3. Two Exits or Proper Egress

Every legal basement unit must have:

• A second exit, or

• A compliant egress window large enough for emergency escape
  This is one of the most common areas where illegal basement apartments fail.

✅ 4. Legal Parking Requirements

Markham zoning requires adequate parking for both the primary and secondary unit.
If a lot cannot accommodate the required parking, the basement unit may not be permitted.

✅ 5. Minimum Ceiling Height

Basement apartments must meet Ontario Building Code height requirements, typically around 6’5” (1.95m) in most finished areas.

✅ 6. Separate Heating & Ventilation Compliance

HVAC systems must properly serve both units.
Some homes may require additional ventilation, ductwork, or independent heating controls.

🛑 What Makes a Basement Apartment Illegal?

Your basement apartment is considered illegal if:

• It was finished without permits

• It does not meet Fire Code standards

• Ceiling height is too low

• There is no secondary exit or proper egress window

• The home lacks required parking

• It fails inspection after construction

Illegal units can lead to:

• Fines

• Mandatory closure

• Forced removal of tenants

• Difficulties when selling your home

• Reduced home value

• Insurance claim denial in case of fire

💡 Buying a Home With a Basement Apartment?

As the Top Realtor in Markham, Michael John Lau helps buyers verify:
✅ Whether the basement unit is legal
✅ Whether proper permits were issued
✅ Whether the suite can be legalized
✅ What rental income to expect
✅ Risks of buying a home with an illegal suite

A legal basement apartment can significantly increase your home’s value AND provide rental income but only if done properly.

💡 Thinking of Legalizing Your Basement Apartment?

Michael can connect you with:

• Licensed contractors

• Designers and engineers

• Permit application support

• Fire Code inspection professionals

Legalizing a basement apartment can add major value to your home, especially in high-demand areas like Unionville, Wismer, and Greensborough.

📞 Work With Michael John Lau Markham’s Trusted Real Estate Expert

Whether you're buying, selling, or upgrading your home, trust Michael John Lau, the Top Realtor in Markham, to guide you with expert advice and proven results.

👉 Visit www.callmikelau.com to get started today.