In August, several areas of Montreal and Laval were hit by torrential rains of an intensity rarely seen. In just a few hours, heavy rainfall saturated municipal infrastructures and put roofs to the test. Flat roofs, which are widespread in the region, are particularly vulnerable during such events, as they depend entirely on the proper functioning of drains. When these become blocked, the consequences can be serious, ranging from water infiltration to structural damage.
Why do drains become blocked during heavy rainfall?
Extreme rains carry more than just water. They bring with them a great deal of debris, which quickly accumulates and clogs drains.
- Accumulation of natural debris Dead leaves, small branches and dust move with the rain and end up in the drain grates.
- Progressive obstruction Over time, sediment or gravel from the roof can also slow down the flow.
- Special features of flat roofs Unlike pitched roofs, which let water run off naturally, flat roofs rely exclusively on drains to evacuate water.
When drains are blocked, water accumulates and stagnates. This ponding puts unusual pressure on the membrane and joints. In just a few hours, a seemingly solid roof can be weakened.
The consequences of a blocked drain
A blocked drain does more than cause a puddle on your roof. The repercussions are much more serious.
- Water infiltration water always finds a loophole. It seeps through cracks and reaches ceilings, interior walls and even electrical installations.
- Structural overload Water is heavy. A few centimetres accumulated on a flat roof represents several hundred kilos. This overload can weaken the roof structure.
- Premature wear of the roof The repeated cycles of stagnation, evaporation and drying accelerate material ageing. The membrane cracks more quickly and the roof’s lifespan is reduced.
- Costly damage Seepage: beyond the roof, seepage often leads to major interior repairs and mold growth, compromising the health of the home.
These problems show just how serious the long-term consequences of neglected maintenance can be.
Best practices to prevent blockages
The best protection is prevention. A few simple steps, taken regularly, can prevent most accidents.
- Regular inspection Inspect drains and gutters several times a year, especially in spring and fall, to help identify the beginnings of blockages.
- Duct cleaning Cleaning: remove leaves, mud and debris that impede the smooth flow of water.
- Vegetation management Vegetation management: prune nearby trees to limit the amount of debris falling on the roof.
- Backflow prevention valves Install this device to prevent sewage water from flowing back into the pipes during heavy rainfall.
- Slope adjustment Water management: redesign the area around the house to direct water away from the foundation and avoid accumulation near the walls.
- Temporary protective barriers Use cofferdams or watertight panels to protect ground-floor openings.
These simple yet effective measures offer real peace of mind to homeowners, especially in a context of increasing extreme rainfall events.
Toitures LV’s expertise
At Toitures LVIn August, we witnessed first-hand the effects of the torrential rains. In the space of a few days, our teams received a record number of emergency calls, mainly for blocked drains and submerged flat roofs. This experience confirms our conviction that prevention is essential.
We offer our expertise to support homeowners before, during and after bad weather.
- 24/7 emergency service ready to intervene quickly to limit damage.
- Preventive inspections to anticipate problems and propose appropriate solutions.
- Complete maintenance of drains and roof membranes to ensure optimum water drainage at all times.
- Personalized advice based on the configuration of each roof and its immediate environment.
With our team, you can count on reliable, responsive support designed to extend the life of your roofs and avoid costly repairs.
Conclusion
August’s torrential rains were a reminder of the vulnerability of homes to extreme weather events. Roof drains play a central role in protecting your home, but they need regular attention. A simple blockage can have major consequences, whereas preventive maintenance and the expertise of a qualified team can give you peace of mind.
Toitures LV remains your trusted partner in the Greater Montreal and Laval areas for all maintenance, repair and prevention of roofing and drainage problems.
