Additional Dwelling Units

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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

In accordance with the Small Multi-Unit Residential Registration Bylaw, additional dwelling units are required to be registered with the City. This includes both new ADUs and existing ADUs created without a building permit.

How to register your additional dwelling unit

Obtain a building permit for the construction of the ADU (see Submitting a building permit application section below for more information);
Submit with your permit application a completed Small Multi-Unit Residential Registration form filled and signed by the property owner;
Pay the registration fee (billed on the permit application).

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 extension 4271.

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.

For single detached dwellings, a total of four dwelling units are permitted on a lot. This includes the primary dwelling unit together with:

Up to three additional dwelling units located within the same building as the primary dwelling unit, or
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
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

Parking requirements

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 must be 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.

Submitting a building 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.

Permit application submission requirements

Depending on your project, there are specific drawings and documents required to be submitted with your permit application. Click on the link below that best describes your project for the list of submission requirements and Building Code requirements. Please have your drawings and documents ready in PDF format before starting your online application.

Interior renovations to create one additional dwelling unit

Interior renovations to create multiple additional dwelling units

Build an addition to create one additional dwelling unit

Build an addition to create multiple additional dwelling units

Build a detached additional dwelling unit or convert an existing detached building