The City of Richmond Hill has passed By-law 143-24 on December 11, 2024 under section 34 of the Planning Act, R.S.O. 1990.

The purpose and effect of this amending Zoning By-law 143-24 is to permit Additional Residential Units (ARU) within any zone that permits single detached dwellings, semi-detached dwellings and certain forms of townhouses and other dwelling types with certain restrictions.

A maximum of three (3) Additional Residential Units shall be permitted on a lot in addition to the primary dwelling unit, provided the total number of dwelling units per lot does not exceed four (4) and provided the number of Additional Residential units in an Accessory Residential Building does not exceed two (2) subject to the appropriate development standards.

The lot or parcel is required to be separately serviced by municipal sewage works and drinking water system.

All applicable law, as set out by the Ontario Building Code, still applies.

For all requirements and restrictions refer to By-law 143-24, on file with the Office of the Clerk. 

Before you apply for a building permit, it is important to note:

Drawings by qualified professionals

Drawings required as part of the building permit application should be prepared and reviewed by a qualified professional as outlined in the Ontario Building Code. A qualified professional can be an architect, professional engineer or a BCIN qualified designer. Delays in the issuance of your permit can arise if your drawings are not complete and/or do not conform to the OBC and the applicable laws.

Building permit submissions

Building permit submission requirements can differ slightly.

ARU after July 14, 1994

For a newly proposed ARU or a secondary suite that existed after July 14, 1994, a Change of Use permit is required. You must submit:

• Building Permit Application Form
• Schedule 1 Designer Information Form
• Compliance with Applicable Laws Form
• Executed Site Plan Agreement from Development Planning (for properties within site plan control area)
• Site Alteration Permit form Development Engineering (if the new accessory structure is greater than 400 sf)
• TRCA Approval (for properties within regulated area)
• Site plan, floor plans, elevations, sections and details (stamped/sealed by a qualified professional)
• Mechanical drawings, including Energy Efficiency Design Summary and heat loss and heat gain calculations (if a new accessory structure is proposed with an ARU)
• Applicable building permit fee

If your house is less than five years old, the proposed renovation must satisfy the full construction requirements under the Ontario Building Code.

The Building Code recognizes the challenges associated with older buildings. Therefore, if your house is at least five years old, you may be subject to less stringent requirements under the Ontario Building Code.

Existing ARU prior to July 14, 1994

If your ARU has been in existence prior to July 14, 1994, a Change of Use permit is not required and zoning exemptions may apply; however, you must still apply for a building permit and comply with the Ontario Fire Code (Retrofit section 9.8).

In addition to the required list of documents, you must also prove the ARU existed on or before July 14, 1994 by submitting:

• An affidavit, sworn before a notary public or commissioner of oath confirming the date of construction of the second unit and confirming that the unit has, either currently or in the past, been occupied as a dwelling unit.

And any one of the following:

• past rent cheques
• assessment roll information
• lease agreement(s)
• installation date of second hydro meter
• utility bills for both units; or
• an affidavit from past tenant(s), sworn before a notary public or commissioner of oath confirming the occupancy date(s) (affidavit must include former tenant's current address and phone number)

Please note: real estate listings are not acceptable forms of proof.

Apply for a building permit.

Once the building permit has been issued, construction can begin. As required by the Ontario Building Code, a building inspector must review the work at various stages of construction. The property owner or his/her agent is responsible for notifying the City's Building Division when different stages of construction are ready for inspection.

You can book an inspection by completing the Inspection Request Form.

Once all inspections are completed, an Occupancy Permit will be issued.

Please note: For building permits subject to retrofit section 9.8 of the OFC (i.e. if your ARU was in existence prior to July 14, 1994), you must book the inspection with the Richmond Hill Fire and Emergency Services by calling 905-883-5444.