Accessory Apartments - Town of Ajax

Accessory Apartments

Accessory apartmentsAn accessory apartment (a.k.a. in-law suite, basement apartment, granny flat or nanny suite) is defined as a separate dwelling unit that is located within the structure of a principal dwelling unit and which is secondary to the principal dwelling.

Homeowners can benefit from the income generated from accessory apartments as well as provide an affordable housing option within the Town. An accessory apartment comprises of a living area, kitchen, bedroom and bathroom. 

Only one accessory apartment is permitted in a dwelling unit. All accessory apartments, new and existing, require a building permit.

Zoning Requirements

Accessory apartments are permitted in a single detached or semi-detached dwelling in all residential zones, excluding RM4, RM5, and RM6, provided the property meets the zoning requirements.

Accessory apartments are not permitted in townhouses.

To permit an accessory apartment in a dwelling unit the property must meet the following requirements:

  • Minimum of 3 off-street parking spaces - 2 parking spaces for the principal dwelling unit and 1 additional parking space for the accessory apartment.
  • Minimum gross floor area of 25 m² (269 ft²) and the total gross floor area of the accessory apartment is not more than the ground floor area of the dwelling in which it is located.

Accessory apartments used or occupied on/or before November 16, 1995 are not required to meet the zoning requirements as Section 76(1) of the Planning Act "grandfathers" these dwelling units, however a building permit is required.

Building Code Requirements

The Ontario Building Code (OBC) requirements vary according to the age of the accessory apartment and dwelling unit.

More Than Five Years Old

When the dwelling unit is older than five years, the accessory apartment is reviewed under Part 11, Division B of the OBC. The majority of accessory apartments constructed in the Town of Ajax fall into this category; Building Approvals have created the accessory apartment guide to assist residents.

Less Than Five Years Old

When the dwelling unit is less than five years old, the accessory apartment is reviewed under Part 9, Division B of the OBC, the construction requirements of the OBC are more restrictive. The accessory apartment guide can be used to assist applicants with the building permit submission requirements, but the Building Code requirements do not apply.

Typical Building Code requirements are as follows:

  • Minimum window areas for light are 10% of the floor area for living/dining rooms, and 5% of the floor area for bedrooms
  • 45 minute fire separation
  • Hard-wired, interconnected smoke alarms located within each dwelling unit, bedrooms and all shared areas
  • Carbon monoxide detectors, within each dwelling unit adjacent to each sleeping area

Section 9.8, Ontario Fire Code

An accessory apartment existing prior to July 14, 1994 is reviewed under Section 9.8 of the Ontario Fire Code (OFC). Please note, major alterations (such as relocating partitions and/or plumbing, enlarging/adding windows, etc.) require review under the OBC, see permit requirements for accessory apartments more than five years old.

Accessory apartments reviewed under Section 9.8 of the OFC are not required to meet the zoning requirements as Section 76(1) of the Planning Act "grandfathers" houses with two dwelling units used or occupied on/or before November 16, 1995.

To determine if the apartment was constructed prior to July 14, 1994 an inspection performed by an Ajax Fire Prevention Inspector is required. Once completed a Notice of Violation Report is provided to the property owner outlining the required remedial construction. The building permit application (9.8 OFC requirements) is submitted to and issued through Building Approvals; however the plans examination and inspections are completed by theAjax Fire Prevention and Public Safety Division.

For more information regarding accessory apartments reviewed under the OFC please contact the Ajax Fire Prevention and Public Safety Division at 905-683-4481.

Other Approvals

In addition to the building permit you may be required to obtain approvals from one or more of the following:

Be advised this is not a complete list and other approvals may be required.

For more information, please contact us at 905-619-2529 ext 3652.