Residential Accessory Buildings

A residential accessory building is a detached structure with a separate or secondary use to your house. It must be located on the same lot as your dwelling and cannot be used for commercial purposes or for habitation.

Some examples of accessory buildings include garden sheds, gazebos, and garages.

Do I need a Permit?

Where accessory to a detached house, semi-detached house or row house, a Building Permit is not required for the construction of a detached accessory structure (garage, carport, gazebo) provided it is not more than 15 square metres, is not more than one storey and does not have plumbing. For all other uses, a Building Permit is not required for the construction of a detached accessory structure provided it is not more than 10 square metres and does not have plumbing. Garages and carports attached to the principal dwelling, regardless of size, are considered to be additions and always require a Building Permit.

Note: Although a Building Permit may not be required for detached structures, all accessory buildings must meet Zoning By-Law requirements and other applicable provincial and municipal regulations.

Apply for a Building Permit

When building a residential accessory structure, you will need to complete:

Application to Construct or Demolish(PDF, 146.95 KB)

You will also need to submit:

• A Site Plan that shows your existing house and the size and location of the proposed accessory building. The Site Plan must also include:
  • Title, scale, north arrow, and property dimensions
  • Legal description including lot and plan number, street name and municipal address number
  • Setbacks to all property lines for the existing dwelling and the proposed accessory building (including roof/eave overhang)
  • Any right-of-ways and/or easements
  • Location and size of all accessory buildings, porches, decks, or swimming pools
  • Front yard landscaping, such as a driveway or sidewalks (if applicable)
  • Location of existing septic system (if applicable)
• Detailed construction drawings, usually in the form of floor plans and elevations, including:
  • Dimensions of proposed accessory building, including the height from grade to roof peak
  • Slab, foundation wall, or pier construction details including size, depth, and compressive strength of concrete
  • Width, location, and lintel size of all openings
  • Size, spacing, and grade of studs and any structural members
  • Roof framing: size, spacing, and grade of rafters, showing support details at all bearing points; or, if using trusses, the manufacturer’s engineered drawings (request these from your truss supplier)
  • View a sample drawing(PDF, 62.65 KB)
• Building Permit Fee

To ensure your application is complete refer to the:

Accessory Building Checklist(PDF, 600.64 KB)