Adding an apartment (additional dwelling units)

Important things to consider before adding a unit to your home

• If you are adding and/or building a unit in an existing dwelling, you need a building permit before proceeding. The construction may include alterations of existing walls, enlarging any window, adding a new exterior door or an internal shared entrance, or even include an addition however, even if there is limited or no work proposed, the proposed “Change of Use” must be reviewed to ensure compliance with the provisions of the Ontario Building Code and other applicable law.
• Under new Provincial changes, where permitted, lots served by municipal water and wastewater may benefit in having up to two additional dwellings. This could be a combination totaling two apartments within the same building that are subsidiary to the principal dwelling or an apartment in combination with a coach house on the same lot.
• Where permitted, lots served by one or more private services (i.e., septic or well water) are limited to one additional dwelling or coach house. Refer to the Ottawa Septic Office to confirm existing septic can accommodate the additional load.
• Where two additional dwelling units are being added subsidiary to and within the principal building, under the requirements of the Ontario Building Code, a person qualified to take design responsibility must be registered to do so under a Building Code Identification Number identifier.
• Exceptions in the building code allow for a homeowner to take design responsibility when adding up to one additional dwelling unit where no other additional dwelling unit exists, or for a permit to construct a coach house.  
• The new unit must be on the same lot as the principal dwelling unit and must have separate access on the ground floor of a principal dwelling (unless building or fire codes allow alternate means). 
• No additional parking space is required but where a new one is provided, it cannot be located in the front yard. Tandem parking in the existing driveway is permitted.
   

Development information officers

In order to provide effective service to clients, the Development Information Service is changing, as of August 1, 2023, in-person service will be available by appointment only.  If you require the services of a development information officer, please call 613-580-2424, extension 23434 or email dioinquiry@ottawa.ca, include the subject address, proposed use, and other pertinent information relevant to the inquiry.  Upon receipt of the inquiry, a phone call or an email response will be provided within 2 to 3 business days, in the event more information is required there will be options to allow for further discussion.

Adding a second unit in an existing house – Ontario Building Code Information

Exceptions

• Prior to 2005, secondary dwelling units were permitted in the following former municipalities. All units that existed before 2005 in these areas must comply with the Ontario Building Code and Fire Code:
  • Cumberland-Urban
  • Gloucester
  • Nepean-Urban
  • Osgoode
  • Goulbourn
  • West Carleton

Financial considerations

• Your property taxes, as determined by the Municipal Property Assessment Corporation, may change as a result of adding additional dwelling units to your home.
• Rent counts as additional income under the Income Tax Act, so adding additional dwelling units will affect your income taxes.
• Notify your insurance company or broker as early as possible about your plan to build additional dwelling units. Your policy may need to be adjusted to reflect the changes in liability and the adjusted value of your home after the addition is completed.
• Financial assistance is available through the Canada Mortgage and Housing Corporation’s Homeowner Residential Rehabilitation Assistance Program for certain additional dwelling units.

• Application for a Permit to construct or demolish
• Applicable fee
• Two complete sets of plans that are legible and drawn to conventional scale

Approximate cost: Refer to Applicable fees

Approximate timeline

Approximate timeline based on City Council approved enhanced service level:• First review - 15 business days

At key stages of building construction, your work must be inspected to ensure that the applicable stage of completed construction complies with the Ontario Building Code. The permit plans and specifications must be on site and made available to the Building Inspector at the time of inspection. To ensure the availability of a building inspector, you should book inspections 48 hours in advance. The building inspector's name and phone number are identified on the building permit. Failure to have the appropriate inspection performed may result in your having to uncover and expose the work for inspection, or other Orders issued etc.

Building Code Service counters are open for personal services by appointment only. This includes the submission of permit applications, payment of fees and the issuance of permits. 

For clients wishing to submit applications, make payments or pick up permits, visit a Building Code Service counter or make an appointment on the scheduler. 

Application Forms: Application for a Permit to construct or demolish