Home > Services > Home Extension Montreal
Home Extension Montreal
Second storeys, rear additions, four-season sunrooms and garage conversions. Architects, engineering and borough permits managed by one RBQ-licensed team.
RBQ License
5797-3208-01
APCHQ Member
Provincial Association
Liability Insurance
$5,000,000
Workmanship Warranty
1 Year
Home extension
More space, without leaving the home you love
Your family grew. Your work moved home. Your neighbourhood is exactly where you want to stay. In Montreal's market, extending your home is often smarter than moving, but it is also the most demanding renovation there is.
An extension is real construction: zoning analysis, architects, structural engineering, borough permits, foundations, envelope and finishes. Most homeowners are not equipped to coordinate a dozen professionals, and they should not have to be.
Kasa General Contractor delivers extensions as a true turnkey general contractor. Founded by two sons of immigrant builders, with 40+ years of construction in the family, 12 years as general contractors and 500+ projects delivered, we take responsibility for the whole chain.
You choose where you want your home to go. We handle the rest: plans, permits, subcontractors, schedule, inspections and delivery.
Who we work with
Extension projects for every way a Montreal home can grow
Whether you need one more bedroom or a whole new floor, the right type of extension depends on your lot, your structure and your borough's zoning. We help you choose before you commit.
What's included
What our home extension service includes
Why professionals
Why an extension demands a licensed general contractor
An extension touches everything at once: zoning, structure, foundations, envelope and systems. Every one of those layers has to be right, in the right order.
Structural decisions with no room for error
Can your foundation carry a second storey? How does the new roof tie into the old? These questions are answered by engineers we coordinate, before construction, not discovered mid-project.
Permits and zoning handled for you
Setbacks, lot coverage, heights, heritage overlays: Montreal boroughs each apply their own rules. We analyze the zoning, prepare the file with our partner professionals and submit the permit for you.
Legal protection and real warranties
Work above $2,000 legally requires an RBQ-licensed contractor. With licence RBQ 5797-3208-01, $5,000,000 in liability insurance and the RBQ guarantee plan, your investment is protected at every stage.
One schedule, one accountable team
Excavation, concrete, framing, roofing, windows, trades and finishes involve a dozen crews. We sequence all of them so your home stays protected and your timeline stays honest.
What sets us apart
Why Montreal homeowners trust Kasa General Contractor with their extension
Extensions are our specialty: the projects where true turnkey management makes the biggest difference.
True turnkey, one point of contact
Architects, technologists, engineers, permits, subcontractors, schedule and inspections all run through one team. Where other contractors leave you coordinating professionals, we take charge of everything.
RBQ licensed, APCHQ member, insured $5,000,000
Licence RBQ 5797-3208-01, APCHQ membership and $5,000,000 in liability insurance. On a project of this scale, those protections are not a detail; they are the foundation of your peace of mind.
40 years of family craftsmanship
40+ years of construction in the family, 12 years as general contractors, 500+ completed projects, including large-scale renovations. Extensions demand exactly that depth of experience.
Transparent milestones, in your language
Cristian and Samuel walk the site with you at each structural and finishing milestone. In English, French or Spanish, you validate the key decisions before they get built in.
How it works
Our 5-step home extension process in Montreal
From feasibility to delivery, every phase is planned, permitted and inspected before the next one begins.
Free evaluation and feasibility
We visit your property, review your goals and give you a straight answer on what your lot, your structure and your borough will realistically allow. Zoning constraints are identified before you spend a dollar on plans.
Plans, architects and permits
Our partner architects, technologists and engineers produce the construction plans. We prepare the permit file and submit it to your borough on your behalf. Permits typically take 4 to 8 weeks; we use that window to lock in materials and trades.
Foundations and structure
Excavation, footings, foundation and structural framing, engineered and inspected at every milestone. For second storeys, we sequence the work to keep your home weathertight throughout.
Envelope and systems
Roofing, windows, exterior cladding, insulation and soundproofing, then plumbing, electrical and ventilation run by certified trades. The new volume ties into your existing home without thermal bridges or leaks.
Finishes and delivery
Interior finishes bring the new space to life: flooring, walls, trim, lighting. We walk the project with you, complete the joint inspection and deliver with a 1 year labour warranty plus the RBQ guarantee plan.
Zoning and permits
Montreal zoning and permits: what extension projects face
Permits are where extension projects stall when they are improvised. Here is what to expect in Montreal, and what we take off your plate.
Borough permits: 4 to 8 weeks
Every extension requires a construction permit from your borough, supported by professional plans. Standard applications typically take 4 to 8 weeks to be issued. We build that window into the schedule and use it to lock in materials and trades, so no time is lost.
Heritage overlay zones
Areas such as Westmount and Outremont include heritage overlay zones with stricter rules on volumes, exterior materials and rooflines. Applications go through additional review and approval takes longer. We prepare files that anticipate these requirements instead of discovering them late.
What we handle for you
Zoning analysis before design, plans by our partner architects and technologists, the permit application submitted in your name, and the municipal inspections during construction. You sign; we run the process.
Not sure what your borough allows on your lot? That is exactly what the free evaluation answers. We review your property and give you a realistic picture of what can be built, and how long the approvals will take, before you invest in plans.
Check My Project's FeasibilityCosts
What drives the cost of a home extension in Montreal?
No two extensions cost the same, and any contractor quoting a price without plans is guessing. What we can tell you honestly is what drives the number, by type of project.
Second storey additions
The big variables: whether the existing foundation and walls can carry the load, the amount of structural reinforcement required, and keeping the home weathertight during the work. Engineering and roof work weigh heavily in the budget.
Rear extensions and bump-outs
Excavation, footings and foundation set the base cost, then size, the complexity of tying into the existing structure, and what the new space contains: a kitchen or bathroom adds plumbing and electrical scope.
Four-season sunrooms
Glazing quality is the main driver. High-performance windows, insulation and heating are what separate a true four-season room from a three-season porch, and they are where the budget should go.
Garage conversions, ADUs and underpinning
Conversions hinge on insulation, heating and change-of-use compliance. Underpinning is specialized structural work priced by depth, soil conditions and access, and always follows an engineering assessment.
How you get a real number
Kasa General Contractor specializes in major residential projects, typically from $80,000 and up, with completed projects reaching $600,000. After the free evaluation, you receive a detailed professional quote; the $500 quote fee is deducted from your contract when the project goes ahead. Every line is explained in person before you sign anything.
Home extensions in Montreal: your questions answered
Straight answers about timelines, permits, heritage zones and structure.
Related services
Explore our other renovation services in Montreal
An extension often comes with a new kitchen, new bathrooms or a full renovation of the existing floors. One contractor can carry all of it.
Home Renovation
Full-service residential renovations managed from the first plan to the final walkthrough.
Learn more
Kitchen Remodeling
Custom cabinets, countertops, islands and open-concept conversions, design to delivery.
Learn more
Bathroom Remodeling
Showers, vanities, ceramic and waterproofing done to code, from design to delivery.
Learn more
After-Disaster Construction
Reconstruction after fire or water damage, coordinated with your insurer and the city.
Learn moreService areas
Home extensions across Montreal, the West Island and the South Shore
Our teams build extensions throughout Greater Montreal. Call (514) 812-8763 to schedule your free evaluation.
By the numbers
A family of builders, not a company improvised overnight
Founded by Cristian Mora and Samuel Perez, two sons of builders who grew up on their fathers’ job sites before taking over.
40+
years of family experience
Two generations of builders
12
years as general contractors
RBQ licensed from day one
500+
projects delivered
Across Greater Montreal
4,5 / 5
Google rating
Earned one delivery at a time
Client Reviews
What Montreal homeowners say about Kasa Entrepreneur Général
Rated 4.5 out of 5 across 14 verified Google reviews.
Wonderful experience building our patio deck last fall. The job was done quickly with great attention to detail. Solid construction. And when I wanted a change to add a second staircase, no problem at all. Cristian listened and incorporated the new design I asked for. Job well done, I highly recommend Groupe KASA.
shelley craig2 years agoFrom start to finish, we had a very good experience with Groupe Kasa. They transformed my bathroom and we got lots of compliments. They understood our vision and made it reality. We are definitely recommending them.
Geovanni Monchez2 years agoAbsolutely thrilled with the renovation work done by Groupe Kasa on my condo! From start to finish, they exhibited professionalism, attention to detail, and excellent craftsmanship. The team was prompt, courteous, and ensured every aspect of the project was executed to perfection. My condo now looks stunning and fee...
alexia soudin2 years agoI recently hired GroupKasa for a home renovation project, and I couldn't be more pleased with the results. The team displayed exceptional professionalism, completed the job within the agreed timeline, and their attention to detail was impressive. The quality of work exceeded my expectations, making the entire experi...
Ivan Moran2 years agoSam and Cristian were a great help From the initial consultation to the final touches. Their team listened to my ideas and offered great suggestions, resulting in a beautiful and functional space that I absolutely love. I highly recommend them for any home renovation project.
Harold Echeverry2 years agoStart your project
More room to live. Designed, built, delivered.
Tell us how your home needs to grow. We will assess the feasibility, map the permits and give you one accountable team from the first sketch to the final inspection.
RBQ 5797-3208-01. APCHQ member. 1 year labour warranty. Service in English, French and Spanish.