Additional residential dwelling units

Zoning By-law definition of an Additional Residential Dwelling Unit

An “Additional Residential Dwelling Unit” means a Dwelling Unit that is self-contained, subordinate to and located within the same Building or on the same Lot of a primary Dwelling Unit. They are often referred to as “granny flats”, “accessory apartments”, “basement apartments” or “in-law suites”.

When a dwelling contains an additional residential dwelling unit in the main house or in an accessory building, it becomes a two-unit house and must be registered with the City as per the Two-unit Registration By-law.

Registering an additional residential dwelling unit

All additional residential dwelling units are required to be registered with the City as per the Two-unit Registration By-law.

New additional residential dwelling units:

The owner or their authorized agent must get a building permit.

Existing additional residential dwelling units:

Where an existing additional residential dwelling unit was created without a building permit, the current owner or their authorized agent is still required to get a permit.

Registration fees:

In addition to the building permit fee, there is a one-time registration fee for additional residential dwelling units. This fee varies based on whether or not the second unit was built with a permit, and whether or not the owner lives in one of the units.

  • New additional residential dwelling unit where the property is occupied by the owner: $150
  • New additional residential dwelling unit where the property is not occupied by the owner: $300
  • Existing additional residential dwelling unit where the property is occupied by the owner: $300
  • Existing additional residential dwelling unit where the property is not occupied by the owner: $600

Note: Property taxes may be affected by the creation of an additional residential dwelling unit. Specific questions about your property taxes should be directed to the Municipal Property Assessment Corporation (MPAC).

Zoning regulations

Consultation with Zoning Services is recommended. Additional residential dwelling units are subject to various zoning regulations such as maximum sizes and minimum parking requirements. Contact Zoning Services at [email protected] or at 519-837-5615.

Additional residential dwelling units are allowed in:

  • R.1, R.2 and R.3B residential zones.

Additional residential dwelling units are not allowed in:

  • Cluster townhouses in R.3A zones
  • Houses with more than two dwelling units (triplex, four-plex, etc.). Older buildings may be considered legal non-conforming. Contact Zoning Services regarding legal non-conforming statuses.

Additional residential dwelling units located within the main building:

(Section 4.15.1.6 of the Zoning By-law)

  • Cannot exceed 45 per cent of the gross floor area of the building as measured from the interior walls. (all floor levels included)
  • Interior access is required between floor levels, and between the additional residential dwelling unit and the host dwelling unit.
  • Can have a maximum of two bedrooms.
  • Can occupy the whole of the basement.

Additional residential dwelling units located in a separate accessory building:

(Section 4.15.1.7 of the Zoning By-law)

  • Cannot exceed 80 square metres (861 square feet) measured from the interior walls and cannot exceed 45 per cent of the gross floor area of the main building. (all floor levels included)
  • Can have a maximum of two bedrooms.
  • Cannot occupy more than 30% of the yard, including all other accessory buildings and structures.
  • The maximum building height is 5 metres, and cannot exceed the overall building height of the main dwelling.
  • When an additional residential dwelling unit is located above a detached garage, the maximum total building height is 6.1 metres, and cannot exceed the overall building height of the main dwelling.

Contact Zoning Services for more information on required setbacks and access regulations.

Additional residential dwelling unit registration and building permit information

Permits and inspections

Step 1: Permit application

Building permit applications are required to be submitted electronically through the Building Services online portal. As a registered user you can also check the status of your permits, pay fees and book inspections online. Please have your drawings ready in PDF format before starting your online application.

Step 2: Submitting drawings

Overall floor plans of all floor levels are required to be submitted and must be drawn to a recognizable scale. (e.g.: ¼ inch equals one foot) Partial floor plans or photos will not be accepted.

Building permit fees for an additional residential dwelling unit within an existing building are calculated based on the floor area measured to the inside face of walls.  However, where an additional residential unit is being installed in a new building, the fees are calculated based on measurements to the outside face of exterior walls. For this reason all drawings must illustrate wall thicknesses. Single line drawings will not be accepted.

A survey or site plan is required to be submitted.  The following parking requirements should be shown on the site plan.

  • A minimum of one parking space for each additional residential dwelling unit.
  • At least one legal, off-street parking space at least 3 metres by 6 metres located in a garage, carport or side yard for the host unit.
  • Exterior parking spaces must be at least 2.5 metres by 5.5 metres each.
  • Each parking space can be stacked behind the legal, off-street parking space.

If the additional residential dwelling unit will be located in a separate accessory building, the following servicing information should also be shown on the site plan:

  • Lines showing the location of each new service to the accessory building (water, sanitary, etc.) with dimensions relative to the existing building and lot lines.
  • Notes indicating the type of material, size of piping and depth of each service. (water, sanitary, etc.)

All floor plans of the house must be submitted, and should show the following:

  • Total square footage of each floor level measured to the outside of exterior walls.
  • The floor level containing the additional residential dwelling unit must indicate the size of the additional residential dwelling unit measured to the inside face of exterior walls and to the inside face of interior separating walls.
  • Location of fire separations and fire doors.
  • Room sizes and room names (e.g.: washroom, bedroom)
  • Ceiling heights for each room, including any reduced heights under bullheads.
  • Window sizes, including any window wells, and interior and exterior sill heights.
  • Type of wall and ceiling finishes in all rooms. (e.g.: ½” drywall)
  • Location of stairs.
  • Location and size of all doors.
  • Location of all smoke alarms and carbon monoxide alarms.
  • Location of all plumbing fixtures, including host and apartment laundry facilities.
  • Location of heating outlets in each room.

Step 3: Additional documents

A Schedule 1 Designer Information form (page 3) is required to be submitted and must be completed by the person taking responsibility for the design activities. This must be filled out by a qualified designer with a Building Code Identification Number (BCIN). Alternatively, the owner may take responsibility for the design activities without meeting the qualification requirements. If the owner is taking responsibility for the design, sections A, B and D have to be completed. In this case, the basis for exemption from qualification and registration should state “homeowner”.

The property owner must complete a two-unit house registration form. You can find this form online at guelph.ca/building.

You will be notified if any other documents, forms or drawings are required to be submitted.

Step 4: Fees

Once your building permit application is deemed complete, you will be notified by email of the applicable fees to be paid.  The fees must be paid before your application can be placed in order to be reviewed.

Please visit guelph.ca/building for the current fee schedule.

Step 5: Inspection requirements

Once the building permit has been issued, construction can begin. The required inspections are identified on the building permit. Please book an inspection through the Building Services online portal. Please allow 48 hours’ notice for inspections.

An electrical contractor inspection form must be submitted at time of the final building inspection (from a licensed electrical contractor or the Electrical Safety Authority), certifying the additional residential dwelling unit has been inspected and there are no visible fire or shock hazards associated with the electrical system. This report will be required for both new and existing additional residential dwelling units and is in addition to any other electrical permits, inspections or certificates that may be required. You can find the form by visiting guelph.ca/building.

Building Code requirements

The following tables outline minimum Building Code requirements for room sizes and minimum glass areas for windows serving those rooms.

Reference: Sections 9.5 and 9.7 of the Ontario Building Code.

Individual room dimensions

Room type Minimum room size (measured to the inside face of walls) Minimum window glass area, in houses less than 5 years old Minimum window glass area, in houses more than 5 years old
Living room 145 square feet 14.5 square feet 7.25 square feet
Dining room 75 square feet 7.5 square feet 3.75 square feet
Kitchen
  • One bedroom: 40 square feet
  • Two bedrooms: 45 square feet
Windows not required Windows not required
Master bedroom
  • With closet: 95 square feet (not including closet)
  • Without closet: 105 square feet
5 square feet 2.5 square feet
Second bedroom
  • With closet: 65 square feet (not including closet)
  • Without closet: 75 square feet
3.75 square feet 1.9 square feet
Bathroom, utility room, other rooms No minimum  (bathroom must be functional and usable)  Windows not required Windows not required

Combination rooms (open concept primary rooms, not including bathrooms)

Number of bedrooms in apartment Room size (minimum, measured to the inside face of walls) Minimum window glass area serving living/dining room, in houses less than 5 years old Minimum window glass area serving living/dining room, in houses more than 5 years old
Two bedrooms
  • Living room plus dining room plus kitchen: 225 square feet
  • Living room plus dining room only: 180 square feet
18 square feet 9 square feet
One bedroom
  • Living room plus dining room plus kitchen: 193 square feet
  • Living room plus dining room only: 153 square feet
15 square feet 7.5 square feet
Bachelor apartment Living room plus dining room plus kitchen plus bedroom: 145 square feet 14.5 square feet 7.25 square feet

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