Part 3 Residential Alteration

A guide to preparing your part 3 residential alteration building permit application.

A part 3 residential building consists of more than three storeys or is greater than 600 m2. 

Before preparing your permit

Some approvals and permits must be in place before you start preparing your building permit application.

Additional permits and documentation may be required before preparing your building permit application, including:

  • Site plan approval: You must submit an application for site plan approval before applying for a building permit. 

  • Demolition permit: If there is an existing building on your site, you will require a separate demolition permit. A demolition permit is a type of building permit

Project preparation

Detailed information is required to properly evaluate your plans and the unique conditions of your property or unit:

Prior to submitting for a permit application, ensure you have support from the condo board. You will be asked to provide a letter of permission from the condo board at time of permit application.

Development charges do not apply to most residential alterations. If you are adding additional units (such as a basement apartment) to an existing home, it will likely be exempt from development charges. Two additional units can be added to a single or semi-detached home or townhouse without incurring development charges.

Learn more about development charges.

Other considerations

Demolition activities may be eligible  for a reduction in property tax assessment under Section 357 of the Municipal Act which provides municipalities with the authority to cancel, reduce  or refund taxes based on specific criteria.

If you think you are eligible to apply for a property tax adjustment please complete the Application for Cancellation/ Reduction/Refund of Taxes under Section 357 form (pdf) and send to

Deadline for submission is the last day of February, the year following the issuance of a demolition permit. A $20.00 fee will apply. Learn more about property tax assessments