We try to make it as easy as possible for you to obtain a permit for accessory buildings but there is certain information that is required. Incomplete applications merely slow down the process of obtaining the permit.

This information should assist you in obtaining the proper permits with the least fuss possible. The information supplied here is of a general nature, some properties have restrictions that are unique to that site, if you have any questions, please call for specific information.

Complete the application along with a plot (site) plan showing the proposed location. If the building is a kit from a building supply firm, just indicate which kit it is; plans may not be required as these are on file, or submit with your sketches showing at minimum the spans, sizes and types of materials to be used in the construction of the garage or shed.

Please note that there are building code considerations in the design of concrete slabs on grade, please go to the concrete slab design page, as well there are minimum energy efficiency requirements. Please also advise us if there are plans to heat the garage.

Concrete in garage floors and exterior flatwork

Please note, that when ordering the concrete for your garage floor, the Ontario Building Code calls for the following: Compressive Strength

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  1. Except as provided elsewhere in this Part, the compressive strength of unreinforced concrete after 28 days shall be not less than:
    • (a) 32 MPa (4650 psi) for garage and carport floors and all exterior flatwork, and,
    • (b) 15 MPa (2200 psi) for all other applications.
  2. Concrete used for garage and carport floors and exterior steps shall have air entrainment of 5 to 8%.

The Ontario Building Code refers to CSA (Canadian Standards Association) and CSA A23.1" Concrete Materials and Method of Concrete Construction" includes 32MPa air entrained concrete as Class C-2. This is described as a minimum compressive strength of 32 MPa in 28 days, 5 to 8% air using 20mm course aggregate, maximum w/CM of 0.45.

Please note, if your property contains an onsite sewage disposal system you must not construct any buildings closer than 5 metres (17ft) to the tile bed. Indicate on the plot plan where the system is located.

Ottawa River Floodplain

Accessory buildings must also be constructed with their floors above the 1:100 year design flood fringe.


Building permits cannot be issued for an accessory building until the main use is established. This means that in most cases a permit cannot be issued for a detached garage, wood or storage shed until a home has been constructed. The minimum side yard for accessory buildings in most rural and residential zones is 4 feet with very few exceptions. The minimum front yard in most rural and residential zones is 25 feet. The minimum rear yard is 3.3 ft.

Please note that the Ontario Building Code in most cases will require a building constructed closer than 1.5 metres, (5ft) to the property line to be constructed and clad with non-combustible material. Therefore, it is generally more cost effective to plan on 5' setbacks.

In residential zones the accessory building must be constructed behind the main building, in the side and rear yards, an exception being properties that front on the Ottawa River. Accessory buildings cannot be built closer than 2 metres (6.5') to the main building on the lot (spatial separation for fire control).

Apply for a permit here