Accessory buildings 

A permit is required to construct accessory buildings. 

Definition 

Accessory buildings are subordinate to the main building on the property and can detached or attached to it. The purpose of the accessory buildings is to compliment the residential function of the main property.  

Private garage 

A single private detached garage is permitted for semi-detached or detached single-family properties.  

The maximum area allowed is 27.87m² (300 ft²) and a maximum height of 3.65m (12’). Under no circumstances can the garage’s height exceed that of the main building.  

If the garage is detached from the main building, it is considered as a part the said building and is subject to the norms applicable to the said building, as defined in the Table of Uses and Norms. 

Shed or Storage Building 

A single shed or storage building may be erected. It must be located at the rear of the main building at a minimum distance of 0.91m (3’) from the lateral and/or rear land lines. For a corner lot, it must be located behind the secondary front setback. 

The maximum area allowed is 9.29m² (100 ft²) and a maximum height of 3.05m (10’). 

If the shed or storage building is attached to the main building, there shall not be any direct access between the buildings. If it is detached, it must be located at least 3.05m (10’) away from the main building. 

Carport 

A carport is permitted on properties with semi-detached or detached single-family and two-family dwellings. it may not project beyond the front or rear foundation walls of the main building.  

A carport may be built for dwellings having either an interior garage or no garage, provided the total width of the two existing and/or new driveways do no exceed 6.4m (21’). 

If the carport is supported by 2 columns, it must have unobstructed minimum interior dimensions of 2.74m (9’) in width and 6.10m (20’) in length. If the carport is supported by 3 columns, it must have an unobstructed minimum interior dimension of 3.05m (10’) in width and 6.10m (20’) in length. The columns of the carport shall be located at a minimum distance of 0.61m (2’) from the land line. 

The roof edge of the carport shall have a gutter which shall be located at least 0.30m (1’) from the lateral land line. Any drainage from the roof shall be directed towards the street and not towards the lateral yard. 

How to apply for a permit 

1. Check the applicable regulations 

1. Accessory buildings are regulated in Chapter 5 of the Zoning By-law #2217 (PDF).  
2. All building modifications are regulated in the Construction By-law #2593 (PDF).  
3. Costs of permits and fees, including the damage deposit for public property, are listed in the Fee schedule.

NOTE: This is not an exhaustive list and other regulations may apply. If you have any questions pertaining to these regulations, please book an appointment to meet with a member of the Urban Planning Department. 

2. Required documents  

1. A valid Certificate of Location, prepared by a licensed land surveyor. Please consult the Ordre des Arpenteurs-Geomètres du Québec website for an example (PDF).
2. A site plan drawn to scale indicated the position and dimensions of the accessory building. 
3. An itemized contractor’s cost estimate, listing the associated costs of all materials and labour for the project. 
4. If you are not the property owner as listed on Montreal’s property assessment roll, you must complete the following procuration form (PDF).  

NOTE: Additional documents may be requested by the permit agent. 

Other documents (if applicable) 

• If applicable, structural engineer drawings, stamped by a licensed engineer. Please consult the Ordre des Ingénieurs du Québec website. 
• If applicable, architectural drawings, stamped by a licensed architect or architectural technologist. Please consult the Ordre des architectes du Québec website. 

3. Submit a permit application 

1. After preparing the necessary documents, the permit application can be easily completed and submitted online.  
2. You will be provided a reference number following the submission of your application. 

4. Analysis of the permit application 

1. The Urban Planning Department will begin the analysis of your permit application as soon as all required information is submitted. 
2. If additional information is required, a staff member will contact you. 
3. If you have not received timely communication or updates regarding your permit application, we kindly ask you to send us an email at [email protected]. 
4. No work can begin until you receive a valid construction permit. 

5. Issuance and payment of the permit 

1. When the analysis of your permit application request is complete, you will receive an email with steps to pay for the permit. A permit will only be issued once the payment has been successfully received and processed. 
2. Once issued, the construction permit must be visible from the street in front of the property. 

6. Completion of work 

1. Throughout the construction process, the City inspector will visit the site to ensure for compliance with the work listed in the permit description and the applicable municipal by-laws. 
2. After the work is completed, please contact the designated inspector listed in the permit description. 

Have questions? Need assistance to apply for a permit? We are here to help!

Book an appointment to meet with the Urban Planning Department.