Exploring the World of Legal Basement Apartments: Your Comprehensive Guide

While the real estate market fluctuates, one thing remains constant: the demand for affordable housing. In major cities across Canada, rental prices continue to soar, making homeowners search for creative solutions to offset their expenses. Among these solutions, the idea of constructing a legal basement apartment has gained popularity, particularly in regions like Toronto and Montreal, where homeowners are looking to diversify their income streams.

Before delving into the pros and cons of transforming your basement into a rental unit, let’s first understand what it means to have a legal basement apartment in Ontario and Quebec.

Defining a Legal Basement Apartment in Canada:


In Ontario, a legal basement apartment is a secondary unit that complies with the Ontario Building Code requirements. To meet these standards, your property must align with zoning codes, and if your building is over five years old, your second unit must possess the following features:

  • A minimum of 145 square feet of space
  • Ceiling height of at least 1.95 meters
  • Windows that make up at least 5% of the living floor area and 2.5% of the bedroom floor area
  • Facilities for hot and cold water, a sink, kitchen sink, and access to laundry
  • Heating, cooling, and electrical systems approved by an Electrical Safety Authority electrician
  • A fire separation of at least 30 minutes from the main unit
  • A secondary means of escape


On the other side of the Ottawa River in Quebec, the regulations surrounding basement apartments are closely tied to their location. The primary concern at the provincial level is the presence and accessibility of an egress window, which serves as a secondary escape route. This window must be large enough for both a child and an adult to pass through freely, without any anti-intrusion bars.

As you can see, the requirements for legal basement apartments are quite specific, and the exact specifications may vary depending on your property’s location.

Navigating the Codes and Regulations

When considering the codes that must be adhered to, it’s essential to recognize that you’ll be dealing with multiple codes at different levels:


  • Ontario Building Code standards govern your building’s condition in Ontario. If your building is older, it’s advisable to hire a property inspector or general contractor to assess whether any updates are needed before proceeding with a basement apartment.
  • Compliance with Fire Code standards is crucial to ensure the basement is safe during emergencies. The fire department typically conducts this inspection. However, even if you receive approval, your basement apartment is not yet considered legal.
  • Specific municipal by-laws come into play, varying depending on where your property is located. Cities like Toronto, Mississauga, Brampton, Milton, Burlington, and Hamilton have distinct by-laws and processes concerning basement apartments.


  • In Quebec, all buildings, including legal basements, must meet the standards set by the Régie du bâtiment du Québec.
  • Additionally, most municipalities have their own rules and regulations pertaining to basement apartments. For example, Montreal has specific guidelines covering configuration, ventilation, lighting, appliances, exits, and other crucial aspects related to second dwellings.

Calculating the Costs of a Legal Basement

The expenses associated with creating a legal basement apartment can vary significantly based on your location and the current condition of the basement. To provide a benchmark, let’s consider an unfinished basement:

  • In Montreal, the starting cost for a turnkey basement without a bathroom in an area of approximately 900 square feet (e.g., a standard 30x30ft or 25x35ft house) is around $45,000.
  • In Toronto, a similar project starts at approximately $70,000.

However, transforming an unfinished basement into a legal dwelling entails additional expenses. It requires the inclusion of a full bathroom, kitchen, an independent entrance, and other amenities, as well as compliance with building and fire codes. According to experts, this comprehensive transition generally begins at $85,000 or more for a 900-square-foot model.

It’s crucial to note that costs can fluctuate based on your property’s existing setup, local quotes, and the extent of structural work required. To gain a better understanding of your specific project’s cost, consult a trusted professional contractor or basement specialist. They can guide you through the process and collaborate with you to design a space that is both legal and appealing to potential renters.

Renting Out Your Legal Basement: A Step-by-Step Guide

Renting out a legal basement can be a complex process, especially for first-time landlords. To simplify the journey, follow these steps:

  1. Compliance Check: Ensure that your basement apartment meets all necessary codes and by-laws. It should be clean, well-maintained, and equipped with required appliances, smoke detectors, and carbon dioxide detectors.
  2. Professional Photography: High-quality photos can significantly enhance your rental listing. Consider hiring a real estate photographer if you don’t have access to professional equipment.
  3. Detailed Listing: Create a comprehensive listing that showcases any updates made to the apartment. Describe the amenities, available space, and unique perks.
  4. Pricing Strategy: Set a fair market price by conducting research on similar units in your area. Keep in mind that adjusting rent later on can be challenging, so aim for an appropriate rate from the beginning.
  5. Tenant Screening: Interview potential tenants, and consider conducting credit checks, checking references, and verifying their income. Being selective can lead to better long-term experiences with your tenants.

Pros and Cons of Having a Legal Basement Apartment


  • Additional Income: A legal basement apartment can provide a steady secondary income stream, which can help pay down your mortgage, reduce debt, or boost your savings.
  • Increased Property Value: Transforming your basement into a legal dwelling is a proven strategy to enhance your property’s value. Families often seek second dwellings for various purposes, such as nanny suites or rental units.


  • Reduced Privacy: Renting out part of your home means sacrificing some privacy. Living with a tenant in your own house can be an adjustment, and noise from the basement apartment may become a concern.
  • High Initial Costs: Converting an average unfinished basement into a legal living space can be a substantial investment, potentially exceeding $100,000. It may take years to recoup these costs through rental income.
  • Landlord Responsibilities: Once you rent your space, you become a landlord with all the associated stress and responsibilities. Maintenance, repairs, and dealing with tenant-related issues become part of your responsibilities.
  • Tax Implications: Renting out a second unit typically requires payment of rental income tax to the provincial government. It’s crucial to consult a chartered accountant familiar with exemptions and strategies for reducing your rental income tax.

Ready to Transform Your Basement?

While the legalities surrounding basement apartments may seem complex, your basement renovation project doesn’t have to be. Our team of experts at Goliath Basements can guide you through the process and connect you with up to three verified contractors in your local area. Whether you’re in the brainstorming phase or ready to start, we’re here to inspire you with basement renovation ideas and trends to create a space that’s both legal and desirable.

Unlock the hidden potential of your basement with Goliath Basements today, and embark on a transformative journey to enhance your home’s value and your quality of life. Your basement is more than just an extension; it’s an opportunity to redefine your living space.