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Zoning Bylaw definition of an Additional Dwelling Unit
An Additional Dwelling Unit (ADU) 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. An additional dwelling unit does not permit a lodging house type 1. They are often referred to as “accessory apartments”, “basement apartments” or “in-law suites”.
Registering an additional dwelling unit
Additional dwelling units are required to be registered with the City as per the Small Multi-Unit Residential Registration Bylaw.
New additional dwelling units
The owner or their authorized agent must get a building permit.
Existing additional dwelling units
Where an existing additional 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 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 dwelling unit where the property is occupied by the owner: $160
- New additional dwelling unit where the property is not occupied by the owner: $320
- Existing additional dwelling unit where the property is occupied by the owner: $320
- Existing additional dwelling unit where the property is not occupied by the owner: $640
Note: Property taxes may be affected by the creation of additional dwelling unit(s). Specific questions about your property taxes should be directed to the Municipal Property Assessment Corporation (MPAC).
Zoning regulations
Additional dwelling units are subject to various zoning regulations such as maximum sizes and minimum parking requirements. If you are unsure of what the zoning regulations are for your property, please contact Zoning Services at [email protected] or at 519-837-5615.
Additional dwelling units are allowed in:
- Residential RL,1, RL.2, RL.3 and RM.5, and in the MOC and D.2 zones on a lot with a single detached dwelling, semi-detached dwelling or on-street townhouse.
Additional residential dwelling units are not allowed in:
- Cluster townhouses in the RL.4 and RM.6 zones
- Houses with more than two dwelling units (triplex, fourplex, etc.). Older buildings may be considered legal non-conforming. Contact Zoning Services regarding legal non-conforming status.
For single detached dwellings, a total of four dwelling units is permitted on a lot. This includes the primary dwelling unit together with:
(i) Up to three additional dwelling units located within the same building as the primary dwelling unit, or
(ii) Up to two additional dwelling units located within the same building as the primary dwelling unit and one additional dwelling unit in a separate building on the same lot, or
(iii) One additional dwelling unit located in the same building as the primary dwelling unit and up to two additional dwelling units in a separate building on the same lot.
Additional dwelling units are permitted with semi-detached dwellings, duplex dwellings, on-street townhouses, or rear access on-street townhouses to a maximum of 3 dwelling units on a lot.
Additional dwelling units located within the main building
(Section 4.12.1 (f) of the Zoning Bylaw)
- The additional dwelling unit(s) shall have a residential floor area that is less than the primary dwelling unit
- 1.2 metre wide unobstructed pedestrian access is required to a separate entrance for an additional dwelling unit, unless access to the additional dwelling unit is provided directly from a street or lane. A gate may be constructed within the pedestrian access, but no encroachments are permitted within the 1.2 metre width, including exterior stairs, window wells, air conditioners, etc.
- Exterior stairs to storeys above the first storey are prohibited in the front yard, exterior side yard and required interior side yard.
Additional dwelling units located in a separate accessory building
(Section 4.15.1.7 of the Zoning Bylaw)
- Each unit cannot exceed 80 square metres (861 square feet) of residential floor area
- Two additional dwelling units are permitted in one building with a maximum floorplate of 90 square meters
- Cannot occupy more than 30% of the yard, including all other accessory buildings and structures
- The maximum building height is 6.1 metres (measured to the midpoint of the roof)
- A 1.2 metre wide unobstructed pedestrian access is required to the entrance of the additional dwelling unit, unless access to the additional dwelling unit is provided directly from a street or lane. A gate may be constructed within the pedestrian access, but no encroachments are permitted within the 1.2 metre width, including exterior stairs, window wells, air conditioners, etc.
- Setbacks (distance from structure to property lines)
- Interior side and rear yard setback for 1 storey structure or 2 storey with no windows on side or rear – based on the zoning of the property being either 1.5 metres or 1.2 metres depending on the property. Some properties may have increased requirements.
- Interior side and rear yard setback if there are 2nd storey windows facing the lot lines – 3 metres
- Exterior side yard (corner lots) – 4.5 metres or 6 metres depending on the property and no less than the setback of the main dwelling.
- From main dwelling – 3 metres
- Any second storey window, balcony, entrance, or exterior stair to the second storey – 3 metres
Please contact Zoning Services to confirm the setbacks on your property.
Permits and inspections
Step 1: Permit application
Building permit applications are required to be submitted electronically through the Guelph Permit and Application System. 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 dwelling unit within an existing building are calculated based on the floor area measured to the inside face of walls. However, where an additional 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:
- 1.2 metre pedestrian access to the entrance of the additional dwelling unit and any obstructions such as air conditioners etc. A photograph may be required to show the access is unobstructed.
- Parking requirement
- Primary dwelling unit with 1 additional dwelling unit – 1 parking space
- Primary dwelling unit with 2 additional dwelling units – 2 parking spaces
- Primary dwelling unit with 3 additional dwelling units – 3 parking spaces
- Location of the required parking spaces for the additional dwelling unit(s).
- At least one legal, off-street parking space setback a minimum of 6 metres from the front lot line, often located in a garage, carport or side yard for the primary dwelling unit
- Interior parking spaces (in a garage) must be at least 3 metres by 6 metres. Exterior parking spaces must be at least 2.5 metres by 5.5 metres
- Parking spaces can be stacked behind the legal, off-street parking space.
If the additional 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 dwelling unit must indicate the size of the additional 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 inch 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.
View example floor plan and escape window details.
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 the additional dwelling unit 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 Guelph Permit and Application System. 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 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 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 |
|
Windows not required | Windows not required |
| Master bedroom |
|
5 square feet | 2.5 square feet |
| Second bedroom |
|
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 |
|
18 square feet | 9 square feet |
| One bedroom |
|
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 |
Ceiling heights
A minimum ceiling height of 6 feet 5 inches is required in an Additional Dwelling Unit. A minimum of 6 feet 1 inches is permitted under bulkheads within the Additional Dwelling Unit. (e.g.: beams and ducts)
Related materials
Is your property ready for ADU-over?
- Download our quick guide to building an additional dwelling unit on your property.
- Download our step-by-step design and development guide to additional dwelling units on your property
Related pages
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