After the torrential rains of July 2025 dumped 81.6 mm of water on Montreal in just a few hours, thousands of homes in Ahuntsic, Pierrefonds and Brossard were flooded. If you've lived through it, you already know that water in the basement is just the beginning of the problem.
What a lot of people don't know is that moisture seeps in everywhere - including your ventilation ducts. And that's where it really becomes a problem for the health of you and your family.
Post-flood air duct decontamination is more than just cleaning. It's a specialized process that eliminates the mold, bacteria and contaminants that grow in your ventilation system after water damage. Without this professional intervention, you're breathing in these pollutants every time your heating or air-conditioning system runs.
In this guide, we'll explain exactly why it's so important, how it works, and what you need to know to protect your indoor air in Montreal.
Why decontamination is essential after a flood in Montreal
When water invades your basement, it carries with it bacteria, debris and all sorts of contaminants. But the real danger is the moisture left behind.
Montreal, with its humid climate and hot summers, is the perfect environment for mold. It takes just 24 to 48 hours for spores to start growing in damp ducts.
The figures speak for themselves. In Quebec, water-related losses account for $405 million a year in insurance claims. And according to the new flood zone maps of September 2025, 19% of Montreal's population lives in at-risk areas - that's 15,508 residential buildings.
Your ventilation system is like the lungs of your house. If your ducts are contaminated, every time the system starts up, it blows polluted air into every room.
Invisible risks in your pipes after a flood
The problem with duct contamination is that it's invisible. You may have cleaned your entire basement, replaced the carpet, repainted the walls - but if water has touched your ducts, or if moisture has remained in them, you've got a problem.
Molds like Aspergillus and Penicillium love dark, damp environments. Your ventilation ducts are exactly that. These spores multiply rapidly and spread throughout the house via the system.
Bacteria are another matter. Floodwater often contains fecal matter, chemicals and organic debris. When this dries out in your pipes, it creates a layer of contamination that becomes a breeding ground for dangerous bacteria.
What about odors? If you smell musty every time your heating system goes out, it's not just unpleasant. It's a direct sign that something's growing in there.
At Vortex Air, we use antibacterial products approved by Health Canada specifically for this type of situation. No harsh chemicals-just what's needed to remove contaminants while keeping your family safe.
Impacts on health and indoor air quality
Indoor air quality in Montreal is already a challenge with our winters, when houses stay closed for months on end. Add post-flood contamination, and you've got a recipe for serious problems.
Children and asthma sufferers are the most vulnerable. Mould spores can trigger asthma attacks, chronic allergies, eye and throat irritations, and even respiratory infections.
Even if no one in your family has asthma, breathing contaminated air day after day weakens your immune system. Wondering why everyone always has a cold? Your ducts may be to blame.
Montreal's humid climate makes matters worse. Summer, with its heat and humidity, is the perfect season for mold proliferation. In winter, when you heat your home with contaminated ducts, you circulate these pollutants even more efficiently.
Have your ducts inspected before it's too late. At Vortex Air, we offer a free, no-obligation inspection. We come to your home, assess the situation with our endoscopic cameras, and tell you exactly what's going on in your ducts. No pressure, just honesty.
What is air duct decontamination in Montreal?
Post-flood duct decontamination is not like routine cleaning. It's a specialized procedure that follows strict protocols to remove contamination and restore your system to a healthy state.
In Quebec, this type of work is regulated. The Régie du bâtiment du Québec (RBQ) regulates requirements under sections 15.7 and 15.8. This means that the company doing the work must have a valid RBQ license, and technicians must be trained to industry standards.
To be clear: if you try to do it yourself, or hire someone who doesn't have the certifications, your home insurance may refuse to cover future damage. It's that simple.
INVC (Institut National de Ventilation et de Climatisation) and NADCA (National Air Duct Cleaners Association) standards define best practices. At Vortex Air, we are INVC certified and in the process of obtaining our NADCA certification - because we take these standards seriously.
Steps for professional post-flood cleaning
The process always begins with a thorough inspection. We use endoscopic cameras to see inside the ducts and assess the extent of contamination. This allows us to give you an accurate picture of the situation.
Next, we use the SFP (suction-pulse) method combined with HEPA filters. This technique creates negative pressure in your ducts to draw out all contaminants - dust, debris, mold, bacteria - without dispersing them throughout your home.
We don't just vacuum. Every section of your ducts is mechanically brushed to dislodge build-up stuck to the walls. That's the difference between a superficial cleaning and real decontamination.
After mechanical cleaning, a disinfectant with a Health Canada-approved DIN (Drug Identification Number) is applied. This product eliminates any remaining bacteria and mould spores. A fogging technique is used to ensure complete coverage of all interior surfaces.
Drying is the final and often overlooked step. If your ducts remain damp, contamination will simply return. Make sure everything is completely dry before closing the system.
The whole process usually takes between 3 and 6 hours, depending on the size of your system and the level of contamination. We work methodically to make sure we don't miss anything.
Equipment and certification required in Québec
In Quebec, the RBQ requires decontamination companies to have a specific license. It's not just a formality - it's a guarantee that the company complies with safety standards and has the necessary insurance.
Technicians must be trained and certified. At Vortex Air, our team of 5+ technicians undergo continuous training to keep up to date with best practices. We invest in this aspect because your safety depends on it.
Professional equipment makes all the difference. HEPA vacuums, for example, capture 99.97% of 0.3 micron particles. It's this level of filtration that prevents contaminants from spreading throughout your home during cleaning.
Endoscopic cameras allow us to document the condition of your ducts before and after. You can see exactly what we're doing and what the results are. This transparency is important to us.
If you hire someone without certification, you're taking a huge risk. Legally, your homeowner's insurance may refuse to cover any future damage related to air quality. And in human terms, you're putting your family's health at stake.
Entrust your decontamination to certified experts. At Vortex Air, our INVC technicians use the right equipment and follow RBQ protocols to the letter. We never cut corners when it comes to your health.
Myth or reality? Misconceptions about air decontamination
There's a lot of confusion around duct cleaning, especially after a flood. We hear all kinds of things, and not all of them are true. Let's clear up a few common myths.
«Clean filters are enough» - Wrong!
Many people think that changing their filters regularly is enough. It's a good habit, but it doesn't protect against post-flood contamination.
A filter catches dust and particles that pass through it. It does nothing for the mold and bacteria already growing IN your ducts.
According to a 2022 Protégez-Vous study, 70% of Quebec homeowners change their filters regularly but have never had their ducts inspected. The result? Systems that look well-maintained but hide serious problems.
After a flood, water or humidity creates a completely different environment. Filters can't do anything about it. It's like trying to put out a forest fire with a glass of water.
«No visible mould, no danger» - Wrong too!
If you see mold, it's already an advanced problem. But the absence of mold does not mean that your ducts are healthy.
Molds start out microscopic. By the time you see them with the naked eye, they've already been growing for some time. And in dark, inaccessible ducts, you can have significant contamination without ever seeing it.
Humidity alone is enough. If your ducts have been exposed to moisture from a flood, even briefly, the conditions are ripe for proliferation. All it takes is high humidity and a little time.
Invisible contaminants are often the most dangerous. Spores in the air, bacteria, VOCs (volatile organic compounds) - you can't see them with the naked eye, but they directly affect your health.
That's why a camera inspection is so important. We can see exactly what's going on inside and give you the straight goods.
«I can do it myself» - Illegal and risky
The desire to save money is understandable. But decontaminating pipes after a flood isn't a DIY project.
First of all, it's illegal in Quebec under article 15.8 of the RBQ. This kind of work requires a professional license. If you do it yourself and there's a problem later, your insurance will refuse to pay.
Secondly, it's dangerous. Without the right equipment, you risk dispersing contaminants throughout your home. A standard residential vacuum cleaner can't filter mold spores-it simply blows them into the air.
Commercially available cleaning products are not designed to decontaminate. Using the wrong product can damage your pipes or create dangerous chemical reactions.
And frankly, without training, you can easily miss contaminated sections. Ventilation ducts are complex, with elbows, junctions and hard-to-reach areas. Partial contamination is almost as bad as no cleaning at all.
Ask for our free guide to safe post-disaster decontamination. It explains what to look out for, what questions to ask contractors, and how to protect your family. It's free and there's no obligation - we just want to help you make informed decisions.
How much does it cost to decontaminate air ducts after a flood?
The question of cost always comes up. It's normal - after a flood, you already have so many expenses that every dollar counts.
For complete duct decontamination after a flood in Montreal, expect to pay between 1,000 $ and 6,000 $. Yes, that's a wide range, but several factors influence the final price.
The good news? Financial assistance is available for Montreal residents affected by the floods. The City of Montreal is offering up to 500 $ for certain decontamination work following the events of July 2025. Ask your borough for details.
And your home insurance normally covers this type of damage if you have sewer backup or flood protection. But beware: they will require proof that the work was done by an RBQ-certified company.
Factors influencing price
The size of your system is the main factor. A 1,000-square-foot bungalow with a single system costs less than a 3,000-square-foot house with two separate systems and an air exchanger.
The level of contamination also plays a role. If water has directly touched your pipes, or if mold is advanced, it takes more time and specialized products. In some cases, sections of ductwork may even have to be replaced.
The accessibility of your system counts. Easily accessible ducts clean faster. If your ducts run through tight spaces or require you to dismantle structures, this increases work time.
Urgency can affect the price. If you need a quick turnaround - for example, before your insurer comes to inspect - some companies charge extra. At Vortex Air, we keep our prices transparent, no matter the timing.
Replacement of damaged components is extra. If your air exchanger or certain sections of ductwork are beyond repair, this adds to the basic cost of decontamination.
Financial assistance and insurance available in Montréal
After the floods of July 2025, the City of Montreal set up a financial assistance program for affected homeowners. Up to 500 $ can be granted for decontamination and dewatering work.
To qualify, you must live in a recognized disaster zone and have proof of damage. Contact your borough - Ahuntsic-Cartierville, Pierrefonds-Roxboro and many others have offices dedicated to post-flood assistance.
Your home insurance, if you have water protection, should cover decontamination. But they'll ask for detailed invoices and proof that the work meets RBQ standards. That's why hiring a certified company isn't just recommended-it's essential.
Some insurers even require a post-work inspection to confirm that decontamination is complete. We work regularly with insurance companies and are familiar with their requirements. We can provide all the necessary documentation for your claim.
The ROI on your health and energy efficiency is worth the investment. Clean ducts improve air circulation, reduce your heating and cooling bill by 15 to 20%, and extend the life of your system. Not to mention the long-term health care savings.
Get a free, no-obligation quote. We come to your home, assess the situation, and give you a clear, honest price. No surprises, no pressure. You decide if it makes sense for you.
How to choose a reliable decontamination company in Montreal
After a flood, you're vulnerable. And unfortunately, some companies take advantage of this situation. Here's how to protect your investment and your family.
First thing to check: the RBQ license. It's mandatory in Quebec for this type of work. Ask for the number and check it on the RBQ website. If a company refuses to give you its license number, run away.
INVC and NADCA certifications demonstrate a commitment to industry standards. These organizations train technicians and auditors
and member practices. It's a good indicator of professionalism.
Local experience counts. A company that knows Montreal understands the specific challenges: the humid climate, the old buildings on the Plateau, the wartime homes in Rosemont, the bungalows in the suburbs. Each type of property has its own particularities.
Prices should be completely transparent. Beware of low estimates that inflate once the work has begun, or super-high prices with no clear justification. A good contractor will explain exactly what is included.
Verifiable references speak for themselves. Ask for recent testimonials, especially from customers who have been in similar situations. At Vortex Air, we've served over 500 customers in Montreal and on the North and South Shores. We can put you in touch with satisfied customers.
Why choose Ventilation Vortex Air
We're not the biggest company in Montreal, and that's precisely our strength. At Vortex Air, you speak directly to Mohamed or Omar, the owners. No call centers, no subcontractors - just a local team that really cares.
We have over 10 years of combined experience in the air quality industry. Our team of 5+ INVC-certified technicians knows Montreal like the back of their hand. We've worked in every neighborhood, from Old Montreal to Saint-Laurent, from Ahuntsic to Brossard.
Our approach is simple: honesty first. If your ducts don't need complete decontamination, we'll tell you. We never recommend unnecessary services just to pad the bill. Our reputation is worth more than any contract.
We're available 7 days a week, from 7 a.m. to 9 p.m., with a 24/7 emergency hotline. Floods don't happen during business hours, and we know it. When you need help, we're there.
Our service is bilingual. We speak French and English fluently, because that's what Montreal is all about. You're comfortable in the language of your choice.
Above all, we put people first. Behind every call, there's a stressed-out family who just wants to breathe easy in their home. We understand that, and we treat every customer as we would like to be treated.
Our transparent, no-pressure process
It always starts with a free inspection. We come to your home, look at your pipes with our cameras and assess the situation. You see exactly what we see. No hiding places, no aggressive sales tricks.
Then we give you a clear, detailed quotation. You know exactly what we're going to do, how long it's going to take, and how much it's going to cost. We include everything in the price - no hidden charges that magically appear at the end.
If you decide to go ahead, we plan the certified cleaning at your convenience. We respect your schedule and arrive on time. While we work, we protect your floors and furniture as if it were our own home.
After the cleaning, we show you the results. We take before-and-after photos, give you a full report, and answer any questions you may have. You leave with the peace of mind that the job has been done right.
Call us at 514-214-7492 - our line is open 24/7. Or visit vortexair.ca to book your free inspection online. No pressure, just the honesty and service you deserve.
FAQ - All you need to know about air duct decontamination in Montreal
How long does it take to decontaminate after a flood?
As soon as possible. Ideally within 48 hours of exposure to water or moisture. That's when mold starts to grow. Even if you're past this deadline, do it anyway-better late than never. At Vortex Air, we offer fast service for post-flood situations.
Is home insurance compulsory?
It depends on your policy, but most insurers require RBQ-certified professional decontamination to cover future air quality damage. If you don't, or if you hire someone without a license, your insurance may refuse to pay in the event of a problem. Check with your insurer, but assume that yes, it is required.
What's the difference between cleaning and decontamination?
Regular duct cleaning removes normal dust and debris. Decontamination goes further: it eliminates mold, bacteria and biological contaminants with specialized disinfectants approved by Health Canada. After a flood, you need decontamination, not just cleaning.
Which products are approved by Health Canada?
Disinfectants used for decontamination must have a Health Canada DIN (Drug Identification Number). These products are specifically tested and approved to eliminate pathogens while remaining safe in a residential environment. At Vortex Air, we only use products with DIN numbers - never harsh or unapproved chemicals.
Can I apply for financial assistance from the city?
Yes, following the floods of July 2025, the City of Montreal is offering up to 500 $ of assistance for decontamination work in recognized disaster areas. Contact your borough to find out about eligibility criteria and application procedures. Keep all your invoices - you'll need them for your application.
How often should I clean my ducts in Quebec?
Normally, every 3 to 5 years, according to the CMMTQ (Corporation des maîtres mécaniciens en tuyauterie du Québec). But after a flood, it's immediate. And if you have allergies, pets or smokers in the house, every 2-3 years is better. Montreal's humid climate justifies more frequent maintenance than elsewhere.
How do I know if my ducts contain mold?
Signs include: musty smell when the system is running, visible stains around grilles, aggravation of allergies or asthma, visible dampness in ducts. But mold can be present without any apparent signs. The only way to be sure is an endoscopic camera inspection. We offer this inspection free of charge - give us a call.
What if I've already cleaned it myself?
If it was just a light dusting, it's no big deal. But if you've attempted post-flood decontamination, have it inspected by a certified professional. You may have scattered contaminants or missed areas. For your insurance claim, you'll need documented professional decontamination anyway.
Are ventilation and air exchanger ducts included?
Yes, a complete decontamination includes all the ducts in your ventilation system: the heating and air conditioning ducts, the air exchanger (if you have one), and the return air ducts. Everything that circulates air in your home needs to be cleaned. We inspect the entire system and tell you exactly what needs attention.
How does Ventilation Vortex Air guarantee safety?
We follow CVRI and RBQ protocols to the letter. Our technicians are trained and certified. We use HEPA equipment that captures 99.97% of particles. We use only Health Canada-approved disinfectants. And we show you the whole process - before, during and after. Transparency is our guarantee of quality.
Breathe easier today
After a flood in Montreal, you've got enough to worry about without having to worry about the quality of the air your family breathes. Decontaminating your ventilation ducts isn't just a matter of comfort-it's a matter of health and safety.
With climate change and an increase in intense rainfall events like those of July 2025, flooding will unfortunately become more frequent in our region. Being proactive now protects your family in the long term.
At Ventilation Vortex Air, we understand what you're going through. We're Montrealers like you. We know what it's like to deal with a loss, to deal with insurance companies, to just want a healthy home again.
Our promise is simple: honest, transparent service, done right. We treat you the way we'd like to be treated. No pressure, no hard sell - just the expertise and respect you deserve.
Book your free inspection today. Call us at 514-214-7492 (available 24/7) or visit vortexair.ca. We'll come to your home, assess your ductwork at no cost or obligation, and give you the straight goods.
Protect your air. Protect your family. Protect your investment.
Vortex Air ventilation - Because your health deserves clean air.
9187 Boulevard de l'Acadie, Montreal, QC H4N 3K1
514-214-7492 | info@vortexair.ca | vortexair.ca
Open 7 days a week, from 7 a.m. to 9 p.m. - Emergency 24/7
