Home extension project

Home extension in Montreal

Thinking about expanding your current space? Adding an extension to your home will increase your liveable square footage, whether you decide to build to the side, up top, or down under.

Receive planning advice, quotes from vetted general contractors, and support from a dedicated project manager for a successful basement renovation in Montreal.

How Billdr works

Working with Billdr to complete your home extension will provide you with assistance and support every step of the way. From finding the right general contractor that will get the job done to consistent check-ins to ensure your project is running smoothly, Billdr is here to help guide you through the renovation process with little to no stress.

How it works timeline
How it works

What you can do with your home extension project

Home extension projects have a significant amount of potential. Whether you’re considering extending your home with additional rooms, adding on another floor, or even increasing the space in your attic to transform it into another living space, there are endless possibilities when it comes to bumping up the footprint of your home.

Home extension

An all-seasons sunroom can be a great addition for those wanting to get a full view of the outdoors in the comfort of your own home, even during freezing winters and scorching summers. With double or triple-pane windows and insulation, these rooms are easy spots to control the temperature and can even double as extra bedrooms or spaces to entertain guests.

Attics typically offer only room for extra storage, but why not turn it into another living space in your home? By raising the height of the ceiling, adding insulation, providing heat, and constructing a sturdy staircase that leads to the attic, you’re looking at the next best room in your home.

When a one-story home presents challenges with finding space for your growing family or to host guests, adding on another story can be a smart and easy solution that allows you to stay where you are and expand, and even increase the value of your home. With an additional bedroom and bathroom or even a home office with extra room to spare, you can live bigger by building upward.

Tell us about your project

Get inspired by our past projects

Check out some of our previous home extension projects to see how other Montreal homeowners decided to give their homes a makeover.

Billdr Services

Choose from a wide range of services that will meet the specific needs of your home extension project.

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Project management

Receive personalized support throughout your project, including weekly site visits, progress reports, and budget monitoring.

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Project planning

Get a clear project scope, 2D floors plans, and a detailed budget estimate within a week made by a Billdr project manager.

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Architectural design

Transform your vision into reality with architectural plans to identify project requirements and building permits early.

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Interior design

Billdr partners with experienced interior designers to turn your ideas into reality and create your dream space.

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Unlock peace of mind with a warranty against unforeseen circumstances that may occur during your renovations.

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Montreal only
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Feasibility study

Your feasibility report will be prepared by an OAA licensed architect in collaboration with your Billdr project manager.

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Toronto only


We know how stressful it can be to undertake a home renovation project. That's why we’re here to support you at every project stage, from planning to construction. From facilitating your search for a vetted general contractor to ensuring that your renovation goes smoothly, you can rest assured that your project is in good hands. We’ll be your right-hand person advocating for your vision all the way through so that the final results meet your expectations.

Per square foot, the average cost of a home extension is approximately:

Extended room that is structurally separate from the house foundation:

Standard: $240

Mid-range: $280

High-end: $340

Extended room that is a part of the house foundation:

Standard: $320

Mid-range: $340

High-end: $385

The price of your renovation will also depend on the scope of the project. Our Project managers will help you define your project scope and send you a detailed budget estimate before you meet with general contractors.

For a better idea of how much a home extension will cost, use our home extension cost estimator.

Billdr will help you find the right general contractor for your project. All of the general contractors we work with have gone through a rigorous vetting process to ensure high-quality craftsmanship and strong work ethics. Through our network, you’ll be able to choose from qualified and reliable contractors with valid licenses and insurance that covers personal injury and property damage.

Tell us about your project to set up a personalized phone call and home visit to assess your renovation needs. As soon as your detailed project scope and budget estimate are ready, your project will be live on our network of certified general contractors. Depending on your project’s size, you will then receive two-to-three comparable quotes to choose from.

Since walls or roofs may be altered during a home extension, summer is the ideal time to do this kind of project. In order to have your project in progress during the warmer months, we suggest beginning the planning phase in the spring so you can be ready and equipped to start your project once summer arrives. 

A building permit is required if you plan on modifying how a room is being used (e.g. adding a bathroom, converting a bedroom into a kitchen, adding an extension, etc.) or changing the outside of your property (façade, windows, etc.). To find out if you need to apply for a permit, check with your municipality. You can also read our guides to learn more about building permits in Toronto or building permits in Montreal.

Changes to your project that occur once construction has started are called change orders. Navigating them can be tricky, but that’s why your Billdr project manager is here to help. You can send your change requests to your general contractor in writing, but make sure that your project manager is included in all communications. Before any changes are made, ask what kind of impact these changes will have on your timeline and the costs of your project to avoid unwanted surprises.

Turning home extension ideas into reality

Ready to finally extend your home but are unsure of the specifics? Book a consultation today to learn more about how Billdr can help you!