By Bradley Santos, co-founder of Ö Nettoyage
Clogged gutters in October don’t bother anyone. The leaves are in there, it isn’t raining much, and you tell yourself you’ll deal with it in the spring.
The phone rings in March. A fascia board that has turned black, a stain on the basement ceiling, a section of gutter hanging loose after the thaw. The cause was visible six months earlier.
We have been cleaning gutters in Laval and on the North Shore since 2022. These six types of damage come back every spring. Here is why they happen, and what you can still do this fall.
Key Takeaways
- In Quebec, water damage accounted for 68% of home insurance claims in 2024, at an average cost of $23,550 per claim (Insurance Bureau of Canada, 2025).
- Clogged gutters rarely damage the gutter itself. They damage what sits below: fascia, siding, foundation, driveway.
- Ice forming in a full gutter is the leading cause of gutter leaks and warping (CAA-Québec, 2024).
- The City of Laval recommends cleaning at least twice a year, after the leaves have fallen.
- On the North Shore, the right time is late October. After the first snow, ice locks everything in place until spring.
How do you know if your gutters are clogged?
Clogged gutters show themselves mostly when it rains. The CAA-Québec maintenance guide, published in October 2024, puts water spilling over the edge and a downspout that has stopped flowing at the top of the list. All of it can be checked from the ground, no ladder needed.
- Water spills over the edge during a downpour, in a sheet or in a single stream at one spot.
- The downspout isn’t flowing, or barely, while it’s raining hard.
- Streaks on the siding right below the gutter, or a band of splashed dirt on the ground.
- Something is growing in there. Maple seedlings or moss mean there is soil in the gutter.
- The gutter is sagging or pulling away from the fascia along one section.
- Icicles hang in winter, often in the same spot every year.
One of these, and the gutter has been full for a while. Two or more, and the damage that follows has probably already started.
The 6 types of damage from clogged gutters left uncleaned before winter
For more than ten years, water has been the leading cause of home insurance claims in Quebec. In 2024, it accounted for 68% of all claims, at an average of $23,550 per claim (Insurance Bureau of Canada, 2025 report).
An overflowing gutter sends that water against the house instead of away from it. The six types of damage below are the ones we see most often on our jobs.
1. Fascia and soffits rot
The fascia is the board behind the gutter, and the soffit is the underside of the roof overhang. When the gutter overflows with every rain, water runs over both pieces of wood instead of going down the downspout.
The wood never gets a chance to dry between showers. The paint blisters, the wood turns black, then it goes soft.
We often find it when we unhook a section to empty it: the fascia behind is soft to the touch. This damage hides behind the gutter itself, which is why it gets found so late.
2. Water gets in behind the siding
A full gutter doesn’t only overflow at the front. It also overflows at the back, between the gutter and the wall, right where the siding starts.
Water runs down behind the vinyl or aluminum and finds a joint, a window frame, a nail hole. Health Canada lists water getting in from outside through the walls or the roof among the moisture sources that lead to indoor mould (Health Canada, 2023).
The most common sign is a water ring high on an interior wall, on the side where the gutter overflows. The homeowner suspects the roof, when the gutter is the culprit.
3. Water pools at the base of the foundation
A gutter works like a funnel. It collects the water from a whole section of roof and carries it to a downspout that moves it away from the house.
Clogged, it dumps that same amount of water in a cascade at one spot, straight against the foundation.
The City of Laval asks that gutter water be directed onto the lawn or a flower bed, never toward the street or the neighbour’s lot, and notes that this is a requirement under its bylaws (City of Laval, 2026). Montréal goes further and requires a permeable surface at least 1.5 metres from the foundation (City of Montréal, bylaw 20-030).
An overflowing gutter cancels out those precautions. The soil against the wall stays soaked, water runs down along the foundation and eventually finds a crack. In spring, that means a damp basement, sometimes a leak.
4. Ice warps and tears off the gutter
This one is a Quebec specialty. A gutter full of soggy leaves holds water instead of draining it. At the first freeze, that water becomes a block of ice, and the block grows with every thaw.
According to CAA-Québec, ice forming inside gutters is the main cause of gutter leaks and warping (CAA-Québec, 2024). A gutter filled with wet debris and ice is heavy. The hangers give way, the gutter pulls away from the fascia, the seams open up.
Ice at the edge of the roof causes a second problem. Meltwater builds up behind it and looks for another way out, often into the house, under the shingles (CAA-Québec, 2026). The root cause of these ice dams is attic ventilation, but a full gutter gives them a starting point.
Every spring, we take down sections twisted by ice. They don’t straighten out, so they get replaced.
5. Mould and nests move in
Wet leaves rotting in a gutter make a warm, damp spot sheltered from the wind. Mould, insects and small animals ask for nothing more.
Health Canada is blunt about it: mould will grow wherever there is excess moisture. Among the prevention measures it names, keep gutters and downspouts clear of debris and make sure water drains away from the building (Health Canada, 2023).
Mould that starts in the gutter moves to the soffit, then into the attic. Usually the smell arrives before the stain.
6. The driveway and walkway ice over
The last type of damage is on the ground. Water overflowing from a gutter above a driveway, a front step or a walkway freezes right where people walk.
That makes a patch of ice that comes back in the same spot with every thaw, all winter long. Salt melts it for a day, and it’s back the next, as long as the gutter hasn’t been emptied.
On our fall visits, this is often the first damage the customer mentions, because they slipped on it the winter before.
Home insurance: are neglected gutters covered?
Not always. CAA-Québec explains that gradual seepage through windows or foundation cracks requires a specific endorsement on the policy, and that basic coverage isn’t enough (CAA-Québec, 2026).
We aren’t insurers, and we don’t give advice on that. What helps in every case is dated photos of the gutters’ condition, before and after maintenance. That’s why we hand them over at every visit.
Few people act anyway. In January 2026, a Léger survey conducted for Allstate among 1,527 Canadians showed that 53% planned no measures against water damage (Allstate Canada, 2026). Yet that same year, claims for water coming from outside had nearly doubled at that insurer.
When is the best time to clean your gutters in Quebec?
Twice a year, with fall as the priority. CAA-Québec says “in the fall, after the leaves have fallen” (CAA-Québec, 2024). The City of Laval recommends the same thing: at least twice a year, after the maple keys and leaves have fallen (City of Laval, 2026).
On the North Shore, that lands in late October. Any earlier, the leaves haven’t all come down. Any later, snow gets in the way: in Montréal, the first measurable accumulation usually arrives in early November, according to MétéoMédia (2025).
So the useful window is short. Between the end of leaf fall and the first snow, there are often two to three weeks. That’s why we start booking fall visits as early as September.
Once there is ice in the gutter, it can’t be emptied without risking breaking it. Whatever wasn’t done before the snow waits until spring.
The second cleaning, in spring, removes what winter left behind: shingle grit, seeds, ice debris.
Who do you call for clogged gutters?
Not a roofer, not a plumber. An exterior cleaning service, equipped to work at height and insured to do it.
The roofer steps in if the roof is the problem, the plumber if the underground drain is blocked. The gutter and the downspout are our job.
A gutter cleaning visit from Ö Nettoyage includes:
- Removing debris by hand, one section at a time. No blower pushing everything down the downspout.
- Flushing the downspouts from top to bottom, until the water runs clear at the ground.
- Checking that water drains away from the foundation, and into the ground drain if there is one.
- Inspecting the hangers, seams and fascia, with photos.
- A final walkaround with the customer. We don’t leave until it’s perfect.
A single-family home takes one to two hours. We serve Laval, Blainville, Mirabel, Terrebonne and Greater Montreal.
Overflowing right now? During leaf season, we keep slots open for gutter emergencies. Call 514-713-6053 and we reply within 24 hours.
Can you clean your own gutters?
Yes, under certain conditions. A bungalow, a stable ladder, someone holding it, dry ground and no wind. Gloves, a bucket and a garden hose are then enough for basic maintenance.
Where we say no: in the rain, on a two-storey house, on a sloped lot, or without ladder experience. A two-storey fall onto pavers can’t be undone.
Professional cleaning also comes with an inspection of the hangers, seams and fascia, backed by photos. That inspection is what catches damage 1 through 4 before it costs anything.
Frequently asked questions
How much does gutter cleaning cost?
The price depends on the length of the gutters, the height of the roof, access and how much has built up. A house surrounded by mature trees takes more time than an open lot. The price is confirmed with a free quote, with a reply within 24 hours.
How long does the job take?
One to two hours for a standard single-family home, depending on the length of the gutters and what we find inside. A duplex or a house with several roof levels takes longer. The time estimate comes with the quote.
Do you clean the downspouts too?
Yes, always. A clean gutter with a clogged downspout still overflows. Every downspout is flushed from top to bottom, and drainage is checked at the ground, away from the foundation, as Laval and Montréal require.
What should I do if the gutter is overflowing during the rain?
Move anything that can’t get wet away from the wall, check that the downspout outlet at the ground isn’t blocked by leaves, and take a photo of the overflow. Don’t climb a ladder in the rain. Call us, we put gutter emergencies first during leaf season.
Do gutter guards mean you never have to clean?
They reduce leaf buildup, but shingle grit, seeds and needles still get through. A yearly cleaning is still needed, and we use it to check that the guards haven’t shifted.
In short
Clogged gutters cost nothing as long as it doesn’t rain and it doesn’t freeze. In Quebec, both happen every fall. Fascia, siding, foundation, ice, mould, icy driveway: six types of damage, one cause, one solution.
The window to act sits between the end of leaf fall and the first snow. On the North Shore, that’s counted in weeks. Gutters that haven’t been emptied yet this year get dealt with now, not in spring.
We clean, we flush the downspouts, we inspect and we show you the result before we leave. For the whole envelope of the house, windows and siding included, the Ö-Complete Package does it all in one visit. The full list of fall tasks is in our exterior maintenance checklist.
