When you decide that you need a basement apartment (or an apartment in any part of your house) there are a number of things to consider.

There are a number of things to consider when planning for what the Ontario Building Code, and most municipalities call an accessory apartment.  This page is just a quick overview of some things that must be determined.
The first part of the process is what does the municipality of your house have to say about dividing your house into separate dwelling spaces.
  • Your house is in a zoning bylaw area that may, or may not, allow a house to be divided into separate dwelling spaces.  Most residential zones allow for at least 1 primary dwelling and 1 accessory apartment.


  • Zoning bylaws will restrict an owner’s rights to divide the dwelling based upon several criteria, such as the width of your lot, number of potential parking spaces, available floor area and so on.
    • This can be determined by contacting the planning department of your municipal office and discussing the proposed project with a zoning bylaw advisor.  The advise is dependent on where your project is located. The advisor will discuss bylaws constraining the location of your property.
    • You may need a legal survey (some municipalities insist upon it) of the property to determine what your lot size really is, where your building sits in relation to the lot boundaries and where could possible access to the apartment be for the tenant.

Ontario Building Code (for houses over 5 years old)

  • If the apartment is in the basement, what is the possible ceiling height?
    • The Ontario Building Code requires a minimum ceiling height of 1,950mm (6′  4 3/4″) and
    • in any area that may be used as a path of egress,
    • otherwise have a ceiling height of at least 2030mm (6′ 8″) over 50% of the ceiling with
    • no part of the basement with a ceiling height lower than 1400mm (4′ 7 1/8″)  being counted as part of the living space.)
    • If the ceiling heights are less than this, lowering the basement floor would have to be considered.
  • The existing stairs to the basement would have to be at least 700mm wide from wall to wall (2′ 4″) and have a minimum clear space over the stairs of 1800mm (5′ 10 7/8″).
  • Windows must have a glass area that is at least 2.5% of the floor area of the bedroom and 5% of the floor area of a dining room or living room. Window sizes double for newer homes.

Ontario Building Code (For all houses)

  • The first bedroom must have an area at least
    • 9.8 m² (105.5 ft²) where built-in cabinets are not provided and
    • not less than 8.8 m² (94.72ft²) where built-in cabinets are provided.
  • Subsequent bedrooms must have an are at least not less than 7 m² (75.34ft²) where built-in cabinets are not provided and not less than 6 m² (64.6ft²) where built-in cabinets are provided.
  • In every dwelling unit, an enclosed space of sufficient size shall be provided to accommodate a water closet, lavatory and bathtub or shower stall.
  • A Kitchen area within dwelling units either separate from or in combination with other spaces, shall have an area of not less than 4.2 m² (45.2 ft²) including the area occupied by the base cabinets
  • Combined living, dining, bedroom and kitchen spaces are combined in a dwelling unit that contains sleeping accommodation for not more than two persons, the area of the combined spaces shall be not less than 13.5 m² 145.3 ft²).
  • The unobstructed width of a hallway within a dwelling unit shall be not less than 860 mm (33 1/8″).
  • Unless there is a door that leads directly to the exterior of the building on the same level as the apartment there must be at least on egress (escape) window of sufficient size in compliance with the Ontario Building Code.  Here is a link to EGRESS window requirements. http://measurite.ca/basement-egress-window/
  • All dwelling units must have access to a laundry facility in the building.  This may be shared or separate, but neither occupant may have access to the other dwelling unit to access the facility.