Blog
15 June 2026
A flat roof rarely shows its weaknesses before they become visible inside. A membrane coming loose at an upstand or a partially clogged roof drain can let water seep in for weeks without anyone noticing. For owners of apartment buildings, plexes and commercial buildings in Montreal, preventive maintenance is the simplest way to protect a flat roof.
Here is what preventive flat roof maintenance involves, what is checked during a visit, how often to do it and what it helps prevent.
Quebec’s climate puts stress on roofs all year round. Winter brings snow, ice and freeze-thaw cycles, which work the membrane and its seams. In summer, UV rays and storms add to the strain. Over time, these stresses end up creating small weaknesses.
On a flat roof, water drains slowly. A minor weakness can therefore turn into a leak if no one spots it. Preventive maintenance is about finding these problems while they are still simple to fix.
A maintenance and inspection visit goes further than a quick look from the ground. The Toitures OBM team examines the roof up close, point by point.
Clogged roof drains are a frequent cause of problems on flat roofs. Ponding water puts stress on the membrane and eventually finds the slightest weakness. Leaves, debris and sediment are removed, and the team checks that water drains properly, without lingering puddles.
The overlaps between the membrane rolls are examined to spot any early signs of delamination or opening.
The upstands along parapets and walls, as well as penetrations such as vents, ducts and mechanical equipment bases, are vulnerable areas. Their watertightness is carefully checked.
The team looks for blisters, cracks, delaminated sections and areas where the granulated surface is wearing. These observations help gauge how the roof is aging.
On commercial buildings and apartment buildings, technicians regularly go up on the roof to service air conditioning or ventilation units. Their repeated trips wear the membrane, and a connection can be shifted during a service call. The team therefore pays special attention to the areas around this equipment and the paths leading to it.
An inspection is only valuable if it leads to clear, well-explained recommendations. Depending on what is observed, several next steps are possible.
If the roof is in good condition, cleaning the roof drains and the next visit are enough.
A crack, a delaminated section or resealing around a roof drain or a penetration is handled with a flat roof repair.
If the membrane is aging, resurfacing (cleaning, preparation of the existing membrane and a cap sheet) can extend its life. When it reaches the end of its life, a elastomeric roof replacement is planned ahead of time rather than in a rush. Toitures OBM explains each recommendation and avoids proposing unnecessary work.
One inspection in the spring and another in the fall is a good schedule for most flat roofs.
An additional visit is useful after a windstorm or hailstorm, or after work on the roof, such as the installation of an air conditioning unit or an antenna.
Undetected water infiltration can soak the insulation, damage ceilings and affect the structure. In an apartment building, it can also inconvenience tenants.
With regular maintenance, an elastomeric membrane can protect a building for several decades. Without follow-up, small problems pile up and shorten its service life.
Knowing the condition of your roof makes it possible to plan the work and the budget, instead of reacting to a leak at the worst possible time.
Toitures OBM is located at 1215 Tellier Street in Laval and offers maintenance andflat roof inspection in Montreal, Laval and on the North Shore. The company specializes in elastomeric membrane flat roofs for commercial, industrial and multi-unit buildings, and also builds residential flat roofs.
Toitures OBM is Soprema PAQ+S certified, CAA-Québec Recommended and holds RBQ licence 5778-2823-01. The team can be reached Monday to Friday, from 8 a.m. to 5 p.m.
Yes. Even on a new roof, roof drains can become clogged and equipment can be added to the roof. Regular inspection also makes it possible to track the condition of the membrane over the years.
Removing leaves around a roof drain is possible if roof access is safe. Inspecting the seams, upstands and penetrations, however, requires a roofer’s eye.
The owner receives an explanation of the roof’s condition and clear recommendations, whether it is to continue maintenance or to plan work.
To have your flat roof inspected in Montreal, contact Toitures OBM at 514-449-5469 or request a free quote using the form.
OBM Roofing
Elastomeric membrane specialists for commercial, industrial and multi-unit buildings in Laval, Montreal and the North Shore.
