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Residential Accessory Buildings

An accessory structure is a detached building naturally or normally incidental, subordinate, and exclusively devoted to the principal building and which is located on the same lot or site as the principal building. 

Accessory buildings are not intended to support any occupancy. Typical accessory buildings include, but are not limited to, detached garages, sheds, gazebos, storage buildings and farm shops.

General Information:

Provided the setbacks are met and the use is permitted for the zoning, permits are not required for:

  • Accessory agricultural buildings such as a granary, silo, or three-sided hay shelter 
  • Accessory buildings under 4.5 m in height and not exceeding a ground floor area of 11.2 m2 on a lot with an area less than or equal to 0.8 ha 
  • Accessory buildings under 4.5 m in height and not exceeding a ground floor area of 18.6 m2 on a lot with an area greater than 0.8 ha
  • Minor developments not exceeding 2.0 m in height, where there is an existing dwelling. This includes, but is not limited to a barbecue, composting bin, garbage enclosure, lawn sculpture, privacy screen or bird feeder

General Regulations:

  • An accessory building shall not be considered without a principal building, structure or use 
  • An accessory building shall be considered a permitted or discretionary use depending on the use the accessory building is subordinate to
  • Please see the appropriate zoning district for specific regulations (setback information and site coverage maximums)
  • An accessory building may be considered part of the principal building when it is attached to the principal building by a roof, an open or enclosed development above grade, an above grade floor or any development below grade allowing access between the buildings 
  • An accessory building or structure shall not be constructed over an easement or right-of-way

Foundation Information:

 For a single storey accessory building, not exceeding 55 square metres (600 sqaure feet) one of the following foundations will be required:

  • Wood mud sills provided the building is not of masonry, or masonry veneer construction
  • A concrete floating slab, provided it is at least 100mm (4 inches) thick and walls are anchored every 2.4 metres (8 feet)
  • A 1.2 metre (4 foot) deep concrete frost wall on a strip footing
  • A deep foundation (pile and grade beam) designed and sealed by a professional engineer

For a single storey accessory building exceeding 55 square metres (600 square feet), or a two storey accessory building, one of the following will be required:

  • A 1.2 metre (4 foot) deep concrete frost wall on a strip footing
  • A concrete floating slab, designed and sealed by a professional engineer
  • A deep foundation (pile and grade beam) designed and sealed by a professional engineer

Wall Heights:

Wall height allowances considered without engineering include:

  • 2 x 4 walls, spaced 12 inches on centre, not higher than 9’8”
  • 2 x 6 walls, spaced 16 inches on centre, not higher than 11”8” 

Please note: 

More Information

Planning and Development Services:

Last updated: Tuesday, June 21, 2016
Page ID: 39753