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French Drain Montreal
French drain installation, replacement and foundation waterproofing. Excavation, drain, membrane and landscaping restoration, by one RBQ-licensed team.
RBQ License
5797-3208-01
APCHQ Member
Provincial Association
Liability Insurance
$5,000,000
Workmanship Warranty
1 Year
French drain
The invisible system that keeps your basement dry
A French drain, also called a foundation drain or weeping tile, is a perforated pipe laid at the base of the foundation, next to the footing, in a bed of clear stone covered with a geotextile membrane. It collects groundwater before it pushes on your walls and carries it to a sump pit or the storm sewer.
As long as it works, you forget about it. When it clogs or collapses, water takes the shortest path: your basement. Stains at the bottom of the walls, a damp smell, water on the slab every spring thaw. In Montreal, between clay soil, freeze-thaw cycles and spring rain, most houses built before the 1980s are reaching the end of their original drain.
Kasa General Contractor installs and replaces French drains with its own crew: excavation, drain, membrane, connection and landscaping restoration. Founded by two sons of immigrant builders, with more than 40 years of construction in the family and more than 500 projects delivered, our team treats your foundation like our own.
Our solutions
Three ways to stop a water problem at the source
The right drain depends on your house, your lot and what sits on the other side of the wall. We recommend the solution that fixes the problem, not the one that inflates the bill.
What's included
What our French drain service includes
We dig along the foundation down to the base of the wall, where the drain belongs. Our own crew runs the equipment, and your property is protected for the whole job.
The clogged or collapsed old drain comes out. The foundation wall is cleaned and inspected while it is exposed: it is the only time you can see its cracks, and they are repaired before we go further.
We lay a perforated rigid drain with a continuous slope toward the discharge point, on a bed of clear stone, then cover it with more stone and a geotextile membrane that keeps fine soil from clogging it.
A waterproofing membrane is applied to the foundation wall, often paired with a dimpled drainage membrane. The drain carries the water away, the membrane keeps it from crossing the concrete: the two work together.
The drain is connected to the sump pit or to the network your borough requires, with cleanouts for future inspection and cleaning. We also check the backwater valve while everything is open.
We backfill, compact and grade the soil to slope away from the house, then test the flow before closing up. Restoring the grounds is part of the price, not a separate invoice.
Why professionals
Why a French drain demands a licensed contractor
A French drain is not a pipe in a ditch. It is work at the base of the most expensive structure in your home, and mistakes stay buried.
We dig at the base of your structure
Excavating along a foundation down to the footing means knowing how to shore the trench, protect the wall and the neighbour, and tell a structural crack from a shrinkage crack. This is not landscaping.
Slope and connection leave no margin
A drain without a continuous slope, or poorly connected, holds water instead of draining it. Once backfilled, nobody can see it. That is why we test the flow before closing up.
Legal protection and real warranties
Work over $2,000 legally requires an RBQ-licensed contractor. With RBQ license 5797-3208-01, $5,000,000 in liability insurance and the RBQ guarantee plan, your foundation is protected at every step.
One contract instead of three
Elsewhere, it is an excavator to dig, a specialist for the drain and someone else to redo the yard or the basement. With us, one crew does it all and answers for all of it.
What sets us apart
Why Montreal homeowners trust Kasa General Contractor with their foundation
A specialist stops at the drain. An excavator stops at the backfill. A general contractor sees the problem through to the end.
All done by our own crew
Excavation, drain, membrane, connection and restoration: no step is handed to a subcontractor. The people who dig are the people who lay the drain and answer for it.
Drain, basement and yard under one contract
Has your basement already taken on water? We redo the drain, then the slab, walls and finishes, in the same project and on the same schedule. No other contractor to find.
RBQ license, APCHQ member, $5,000,000 insured
RBQ license 5797-3208-01, APCHQ membership and $5,000,000 in liability insurance. When we dig at the base of your home, these protections are not a detail.
40 years of family know-how, in your language
More than 40 years of construction in the family and 12 years as general contractors. Cristian and Samuel review the installation with you before backfilling, in English, French or Spanish.
How it works
Our 5-step French drain installation process in Montreal
From diagnosis to flow test, each step is signed off before the next one begins. You always know where your project stands.
Free evaluation and diagnosis
We visit your basement and walk around the house to find where the water is coming from. When needed, a camera run through the existing drain shows whether it is blocked, crushed or simply dirty. Sometimes a cleaning is enough, and we tell you so.
Detailed, line-by-line quote
You receive a clear quote: drain length, depth, membrane, connection and restoration, priced per linear foot. Every line is explained in person. No vague numbers, no surprises mid-project.
Permits and planning
We check your borough’s requirements, file the permit if one is needed, have underground utilities located and set a schedule that accounts for the weather.
Excavation, drain and membrane
Our crew digs down to the footing, removes the old drain, repairs cracks, applies the membrane and lays the new drain in clear stone. Cristian or Samuel reviews the installation with you before we backfill.
Restoration and flow test
We backfill, grade, test the flow and leave a clean site. You walk away with a 1-year labour warranty on top of the RBQ guarantee plan.
The Montreal reality
Interior or exterior: what decides it in Montreal
Online guides present the exterior drain as the only real solution. On a Plateau plex or a semi-detached house in Rosemont, reality is more nuanced.
Plexes, semi-detached and row houses
You cannot dig along a shared wall, and access is often tight on the street or lane side. In those cases we combine: an exterior drain where access allows, an interior drain along the walls we cannot expose. It is the most common situation on the island of Montreal.
Is a French drain mandatory in Quebec?
For new construction, yes: the Quebec Construction Code requires the base of foundation walls to be drained, unless the soil drains naturally. For an existing house, no rule forces you to replace an old drain: the condition of the foundation and the basement decides.
Rigid drain or agricultural drain?
The agricultural drain, a flexible corrugated pipe, was the norm in older houses. It crushes under the weight of the soil and clogs faster. We install a BNQ-certified perforated rigid drain, with cleanouts so it can be inspected and cleaned.
Not sure which solution fits your house? That is exactly what the free evaluation answers. We look at your foundation, your lot and your neighbours, and recommend the work that fixes the problem, not the most expensive option.
Have my foundation evaluatedCosts
How much does a French drain cost in Montreal?
A French drain is priced per linear foot. With us, that price covers everything, from the first shovel of dirt to the restored yard. Here is what moves it, with real ranges rather than teaser numbers.
Footing depth
The deeper the foundation, the more digging, shoring and backfill. A full-height basement costs more per foot than a crawl space.
Access and what has to come apart
An open yard is dug by machine. A paved driveway, a deck, stairs or a narrow lane mean more hand work and more restoration.
The condition of the exposed wall
Once the foundation is exposed, cracks are repaired before the membrane goes on. It is the only time to do it properly, and it is built into the quote.
$120 to $180
Per linear foot, all included: excavation, drain, membrane, connection and restoration
Same price
For an interior or exterior drain: access makes the difference, not the rate
$4,800 to $7,200
Example: one 40-foot side of a house
$14,400 to $21,600
Example: the full perimeter of a 120-foot duplex
Prices in effect in September 2026. The exact amount is confirmed in the quote, after the on-site evaluation.
A word about lowball quotes
A price per foot that is far lower almost always hides something: a trench that stops above the footing, an agricultural drain instead of a rigid one, no membrane, or a yard left torn up with a second bill to fix it. We would rather give you an honest number for a drain that will last for decades.
Signs and maintenance
Clogged French drain: clean it or replace it?
A failing drain does not always need replacing. Before we dig, we check what is really going on inside the pipe.
Signs your drain needs a look
- Water or stains at the bottom of basement walls after the snow melts or a heavy rain.
- A white powder on the concrete (efflorescence): water is crossing the wall and leaving its minerals behind.
- Parging that crumbles or peels at the bottom of the foundation, outside.
- A lingering damp or musty smell, even with a dehumidifier running.
- Orange sludge in the sump pit or the cleanouts: that is iron ochre, and it clogs drains.
French drain cleaning: inspect before digging
A camera run through the drain shows whether it is simply dirty, crushed in one spot or finished along its whole length. If a high-pressure French drain cleaning through the cleanouts is enough, that is what we recommend.
Replacement is the answer when the pipe is crushed, has lost its slope, is an old clogged agricultural drain, or when water gets in despite a clean drain. Either way, you see the footage before you decide.
French drains in Montreal: your questions answered
Straight answers about lifespan, depth, permits, timelines and insurance.
A properly installed French drain usually lasts 25 to 40 years. What wears it out is the soil: silt, roots and iron ochre gradually clog the perforations. A rigid drain bedded in clear stone and wrapped in geotextile ages far better than an old agricultural drain laid straight in the dirt.
At the base of the foundation, next to the footing, never above it. In Montreal, footings sit below the frost line, so we usually dig between 1.5 and 2.5 metres depending on the house. A drain set too high misses the water pushing on the bottom of the wall, which is exactly the water that gets into the basement.
It depends on your borough and the scope of the work: excavation, the sewer connection and the backwater valve are all covered by municipal rules. We check your borough’s requirements and file the permit on your behalf when one is required. You don’t have to navigate the process alone.
One side of a house usually takes a few days. A full perimeter takes longer, depending on access, depth and weather. You receive a precise schedule with your quote, and we keep you informed at every step.
Rarely the drain itself, which is treated as normal wear. Damage caused by water infiltration may be covered, depending on your policy. If your basement has already flooded, we can take on the rebuild in coordination with your insurer, on top of the drain.
For an exterior drain, we protect the property during the work, then backfill and grade the soil to slope away from the house. Restoring the grounds is included in our price. For an interior drain, we only open the basement perimeter, and because we are a general contractor, we can redo the slab, walls and finishes under the same contract.
Related services
Explore our other renovation services in Montreal
A French drain is often the first step. Once the foundation is dry, the same contractor can carry the rest of the project.
After-Disaster Construction
Rebuilding after water damage or fire, coordinated with your insurer and the city.
Learn more
Home Renovation
A basement to finish once the foundation is dry? Full renovations managed start to finish.
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Home Extension
Rear additions, second storeys and underpinning, with foundations and drainage designed from day one.
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Commercial Construction
Drainage, foundations and fit-outs for commercial and multi-unit buildings.
Learn moreService areas
French drains across Montreal, the West Island and the South Shore
Our teams install and replace French drains throughout Greater Montreal. Call (514) 812-8763 to book 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
A dry foundation. Dug, drained, protected.
Tell us what you see in your basement. We find where the water comes from, give you an honest price per linear foot and fix the problem with one crew, from the first shovel to the restored yard.
RBQ 5797-3208-01. APCHQ member. 1 year labour warranty. Service in English, French and Spanish.