Looking to renovate your basement?

For many Montréal homeowners, the basement represents a vast amount of untapped potential. Whether you want to accommodate a growing family, set up a home office, or create an independent apartment, maximizing this space is a strategic decision. However, trying to act as your own project manager in an older home in Plateau-Mont-Royal, Rosemont, or Westmount can quickly become complex. Between coordinating the plumber, electrician, drywall finisher, and carpenter, the risks of errors, delays, and cost overruns are high.

For a basement apartment (often referred to as a secondary suite) to be considered compliant in Canada in 2026, several requirements must generally be met, including those based on the National Building Code of Canada and applicable municipal bylaws. Common criteria typically include a minimum ceiling height of around 1.95 m (6 ft 5 in), egress windows providing a minimum unobstructed opening of approximately 0.35 m² per bedroom, and proper fire separation between units. That said, requirements can vary significantly depending on the province, municipality, and type of building. Failing to comply may lead to serious consequences, such as fines, insurance limitations, or restrictions on renting out the unit.

In 2026, the cost of finishing a basement in Canada typically ranges between $60 and $110 per square foot, depending on the scope of work, materials selected, and whether features like a bathroom or custom spaces are included. For a 1,000 sq. ft. basement, homeowners should generally budget between $65,000 and $95,000 for a full renovation, including partitions, a family room, a compliant bedroom, and a bathroom.