Conversion of a plex (duplex, triplex) into a single-family home in Montreal

Converting a duplex or triplex into a single-family home in Montreal is an ambitious project that is increasingly appealing to homeowners seeking more space and personalized amenities. Here are the key points to consider for a successful process.

Regulations and Conditions by Borough

Montreal actively protects its rental housing stock, which makes the conversion process vary from one borough to another. For example:

• Plateau-Mont-Royal and Rosemont prohibit the conversion or merging of units to limit the loss of affordable housing.

• Villeray and Mercier-Hochelaga-Maisonneuve allow the conversion of duplexes, subject to conditions and permit approval, but restrict the conversion of triplexes.

• A conversion permit is required everywhere, and applications must be complete and comply with local zoning regulations.

Challenges and Technical Steps

Conversion requires rigorous planning:

• Analysis of the existing structure, including the foundation's capacity to support new additions, the removal of load-bearing walls, and the management of exterior staircases.

• Upgrading of systems (electricity, plumbing, heating), which are often outdated, especially in duplexes built before 1960.

• Choosing a more modern layout: open concept, redesigned kitchen, creation of bright and accessible spaces, and the addition of balconies or terraces to maximize natural light.

• Compliance with building codes, particularly regarding insulation and energy efficiency.

Modularity and Ergonomics

The current trend is to incorporate flexibility: creating modular spaces that can serve as offices, guest rooms, or secondary living spaces (bachelorette rooms, suites for aging parents). Specialized architects offer customized solutions, sometimes including the addition of mezzanines, additional floors, or backyard extensions.

Financing and Incentives

It is recommended to inquire about municipal, provincial, and federal renovation grant programs: some assistance is available for major renovations, energy efficiency improvements, or heritage conversions.

Table of Key Points for Success

appropriate design, compliance with standards and close coordination with municipal authorities and building professionals.

Zoning Constraints

Before undertaking any residential renovation or conversion work in Montreal, it is essential to thoroughly review the zoning regulations and specific rules for the borough in question. These constraints can have a major impact on the project's feasibility.

Zoning Constraints

1. Land and Building Use: Each sector in Montreal is governed by a zoning plan specifying permitted uses (residential, commercial, mixed). For example, some sectors only allow single-family homes, while others permit multi-unit buildings or even integrated commercial spaces.

2. Density and Maximum Height: Regulations stipulate the permitted density (number of units per lot) and the maximum building height, which can limit expansions or the conversion of an duplex into a single-family home with an additional floor.

3. Setbacks and Building Footprint: The minimum distances to be respected between the building and the property lines (front, rear, sides) must be verified. These margins may affect the addition of extensions or balconies.

Borough-Specific Rules

1. Heritage Protection Programs: Some boroughs have protected sectors where facades, materials, and volumes must adhere to specific standards to preserve their historical character.

2. Conversion Restrictions: In densely populated neighbourhoods like Plateau-Mont-Royal or Rosemont, combining dwellings (for example, converting a duplex into a single-family home) is often prohibited to maintain the supply of rental housing.

3. Permits and Variances: Any major alteration requires a permit issued by the borough. When a project does not meet all the standards, a minor or major variance application can be submitted and reviewed by a neighbourhood committee or a municipal commission.

4. Eco-Neighbourhoods and Environmental Standards: Some boroughs encourage sustainable construction with specific requirements for insulation, eco-friendly materials, and on-site water management.

Practical Advice

• Contact the borough's urban planning department at the earliest stages to ensure your project complies with regulations.

• Consult the online zoning map for Montreal.

• Anticipate the processing times for permits or variances.

• Consult a professional (architect or urban planner) to navigate the technical and regulatory constraints.

Checking these constraints will help you avoid refusals, fines, or unexpected additional costs during your project in Montreal.

For more information

Lineaire, a general contractor, can also provide information about your project, with its team of carpenters and joiners. You can contact them through their website: www.lineaireconstruction.com or on social media @lineaire.entrepreneur.general

Conversion of a plex (duplex, triplex) into a single-family home in Montreal