Accessory Apartments

Accessory apartments are permitted within any single detached dwelling, semi-detached dwelling, semi-detached building, duplex or street townhouse dwelling or within an accessory building (residential only) located in a R1, R2, R3, R5, OSR-A, OS-ORM, AG-A, AG-B or AG-ORM Zone. Subject to compliance with provisions found in section 5.12 of the City of Oshawa Zoning By-law.

• The accessory apartment is not located within hazards lands or areas without safe access as identified by C.L.O.C.A (Central Lake Ontario Conservation Authority).
• The main dwelling is a permitted use within the zone in which it is located. Where the main dwelling is only permitted as an interim use by an “h” holding symbol, accessory apartments shall not be permitted.
• The exterior entrance to an accessory apartment must have a hard surface unobstructed path with a minimum width of 0.81m maintained to street line.
• Minimum parking requirements (details below).
• Minimum landscape open space requirements (50% landscape must be maintained in certain yards).
• You are permitted a maximum of 3 residential dwelling units on your lot, of which, a maximum of 1 accessory unit may be in an accessory building on the property.
• Accessory units within an accessory building must comply with the regulations under Section 5.1 of the City of Oshawa Zoning By-law 60-94, as amended 

A maximum of one accessory unit may be located within an accessory building, subject to compliance with sections 5.1 and 5.12.

Lot Coverage: The most restrictive of the below three determines the maximum permitted lot coverage for all accessory buildings on the lot combined:

• Maximum 8% of the total lot area or,
• Maximum 50% of the lot coverage of the house on the lot (Properties zoned R1-G and R1-H = 100%) or,
• Maximum 60 m2 of ground floor area (properties zoned R1-G and R1-H ground floor area is 90 m2).

Note, when converting an existing accessory building to a dwelling unit section 5.12.1 (q) also applies.

5.12.1(q) Notwithstanding the provisions of Articles 5.1.2, 5.1.3 and 5.1.4 and Sentence 5.12.1(I) of this By-law to the contrary, an accessory building existing as of May 29, 2023 that is accessory to a single detached dwelling, semi-detached dwelling, semi-detached building, duplex or street townhouse dwelling may be used as an accessory apartment subject to the floor area of the accessory apartment in the accessory building not exceeding 60m2 and compliance with the provisions in this Article.

Setbacks: The required distance from the proposed building to the property line.

• The minimum required setback from a interior side and rear lot line is 0.6m ( 2ft)
• The minimum required setback from a exterior side (corner lot) lot line is determined by the minimum required side yard depth for the zone.

Building height: Measured from grade to the highest peak at the building’s front elevation. As defined in section 5.1.3(2).

• Maximum permitted height 4.5 m (14ft9in)
• Maximum permitted height for properties zoned R1-G and R1-H is 5m (16ft4in)

Location on property:

• A minimum distance of 3m must be provided between the main dwelling and the accessory building dwelling. 
•  A hard surface walkway with a unobstructed minimum width of 0.81 m (32 in) must be provided from the accessory dwelling unit entrance to the street line.
• A minimum setback of 30 m from any railway right of way, 14 m from any highway (401/407) property line or 7m from the outer limit of any gas or oil pipeline corridor.
• In most cases, accessory building dwellings cannot be located in the front yard.
• The accessory unit may not be located within any hazard lands or areas without safe access as identified by CLOCA.

If your property does not meet the minimum zoning requirements, you may be interested in applying for a minor variance through the Committee of Adjustment.

One (1) additional parking space is required for each accessory dwelling, in addition to the minimum parking requirements (2 spaces) for the existing single detached dwelling, semi-detached dwelling, duplex or townhouse.  

For a property containing two dwelling units;
Three parking spaces are required, each space is 2.75m x 5.75m
At least one space must be located within a side yard, rear yard, or garage
Two spaces must have unobstructed street access (not parked in tandem)
Minimum 50% front yard and 50% of the exterior side yard must be maintained as landscape open space 
Minimum 50% of the rear yard of a corner lot must be maintained as landscaped open space

For a property containing three dwelling units;
Four parking spaces are required, each space 2.75m x 5.75m
One space must be located within a side yard, rear yard or in a garage 
Three spaces must have direct street access (not parked in tandem) 
Minimum 50% front yard and 50% of the exterior side yard must be maintained as landscape open space
Minimum 50% of the rear yard of a corner lot must be maintained as landscaped open space

The parking spaces which must be directly accessible to the street will often require the curb to be cut. This must be approved by the City of Oshawa (City Street) or the Regional Municipality of Durham (regional road). Please contact Service Oshawa regarding access permits for city streets and contact the Regional Municipality of Durham at durham.ca for curb cuts for regional roads.

The parking spaces often require the curb to be cut. This must be approved by the City of Oshawa (City Street) or the Regional Municipality of Durham (regional road).  Please contact Service Oshawa regarding access permits for city streets and contact the Regional Municipality of Durham for curb cuts on regional roads.

Note: The City of Oshawa monitors, regulates and enforces general parking regulations as outlined by the Traffic By-Laws.

• Permit application form,submit it along with your permit plans and pay a permit fee as outlined by the Building By-law as amended.
• Owner's authorization form will be required if you are not the property owner
• Schedule 1 - located on page 3 of the permit application form
• Plumbing Information - for water distribution sizing form

The below items need to be shown on the site plan.

• Entire property with lot dimensions
• The location and dimensions of all existing buildings (i.e. house, shed, garages) or structures (decks, porches) on the property
• Landscaped areas, walking paths, driveway conditions
• Parking spaces with dimensions (each space must be 5.75m x 2.75m)
• Location of exterior entrances to principal dwelling unit and to accessory apartment
• Demonstrated unobstructed 0.81m wide walkway from accessory apartment exterior entrance to street line. Air conditioner location to be shown
• Setback of the proposed building / structure to any easements, if applicable
• Note, for the construction of a new accessory building dwelling a plan of survey is required. Please ensure your survey is sealed by an Ontario Professional Engineer or Ontario Land Surveyor 

Existing floor plan

• Direction (north arrow)
• Identify all existing construction
• Label all rooms and shared areas
• Floor area of unit/dimensions of each room
• Smoke and CO alarm locations
• Location of laundry facilities
• Location of Stairs
• Means of egress

Proposed floor plans, cross section, elevations

• Direction (north arrow)
• Identify all proposed construction
• Floor area of unit/dimensions of each room
• Smoke and CO Alarm locations
• Window and door types, sizes and location
• Labelled all rooms and shared areas
• Location of proposed and existing plumbing (clearly labelled “new” or existing”)
• Stairs, furnace, laundry location (specify if laundry is shared)
• Location and construction of required fire separations, wall/ceiling fire separations assembly/cross section showing construction
• Location of duct smoke detector device to shut off power/fuel to furnace
• Proposed means of egress and specify any shared common areas
• Exterior lighting location
• If constructing exterior stairs, provide details and cross section showing dimensions, direction of swing/opening of window and include window well details
• Provide elevations of exterior walls where new windows or doors are proposed and provide exposed building face/limiting distance calculations.