Blog
13 July 2026
A well-maintained flat roof can protect a building for several decades. On the other hand, a roof left to itself accumulates small defects that eventually cause leaks. For owners and managers of apartment buildings, plexes and commercial buildings in Laval, preventive maintenance is the simplest way to stay on top of the roof’s condition.
Here is what a preventive maintenance program includes, how often to schedule it and which signs to watch for between visits.
On a flat roof, water flows slowly toward the roof drains thanks to a slight slope. If a drain is partially clogged or the membrane has a crack, water can pool and seep in. A small crack, a seam coming loose or a blocked drain may seem harmless, but left unchecked, they often lead to leaks, wet insulation and bigger repairs.
Preventive maintenance makes it possible to catch these problems early, when a targeted repair is still enough. It also helps you plan larger projects, such as resurfacing or a roof replacement, instead of having to deal with them in a hurry.
In Quebec, flat roofs face demanding conditions. Spring and fall freeze-thaw cycles put stress on materials: water that gets into a hairline crack freezes, expands and widens the opening. Accumulated snow, then the melt, put strain on the roof drains and upstands. In summer, UV rays and heat age the surface of the membrane.
An elastomeric membrane made of SBS modified bitumen is designed to withstand these temperature swings, but it still needs regular follow-up to last.
It all starts with an inspection. The roofer examines the overall condition of the membrane, the seams, upstands, flashings, roof drains and penetrations such as ventilation ducts and equipment supports. This inspection gives a true picture of the roof and makes it possible to set clear priorities.
Roof drains are essential to a flat roof working properly. Leaves, sand and debris build up in them over the seasons. Cleaning the roof drains and checking water drainage reduce the risk of buildup and standing water, especially before winter and during the spring melt.
Seams, membrane upstands and the area around penetrations are the most sensitive parts of a flat roof. Over time, they can crack or come loose. When a defect is found, localized resealing can be done before water gets in.
The inspection also makes it possible to track the aging of the membrane from one year to the next. If the surface shows general wear but the membrane is still sound, resurfacing (cleaning, preparing the existing membrane and applying a cap sheet) can extend its service life. If the damage is extensive, a roof replacement may be recommended, always after an assessment.
As a rule, two inspections a year are recommended: one in spring, to assess the effects of winter, and one in fall, to prepare the roof for the cold season. For an older roof or a commercial building with a lot of equipment on the roof, more frequent follow-up may be warranted.
It’s also wise to have the roof checked after a major weather event: hail, high winds or unusual snow accumulation. These events can cause damage that is hard to see from the ground.
Between two inspections, some signs call for immediate attention:
If you notice any of these signs, it’s best to have the roof inspected without waiting for the next scheduled visit.
Some owners see maintenance as just another expense. Yet regular maintenance generally costs much less than repairs due to leaks that have gone on for a long time, not to mention damage to ceilings, insulation and interior finishes. For an apartment building, it also reduces disruption for tenants.
Finally, an inspection history makes it easier to plan the building’s budget: you know where the roof stands and when to plan for larger work.
Toitures OBM is based at 1215 rue Tellier in Laval. The company specializes in elastomeric membrane flat roofing for commercial, industrial and multi-unit buildings, as well as for residential flat roofs. Laval is one of its main markets, along with Montreal; the team also serves the North Shore.
Its maintenance and inspection service covers roof drains and water drainage, seams, upstands and penetrations, the overall condition of the membrane and cleaning of the roof drains. Toitures OBM is Soprema PAQ+S certified, CAA-Québec Recommended and holds RBQ licence 5778-2823-01. Its recommendations are clear and explained, and they are based on an assessment of the roof’s actual condition.
It covers the overall condition of the membrane, the seams, upstands, flashings, penetrations and roof drains. The drains are cleaned and water drainage is checked. You then receive clear recommendations on what needs to be done, or not.
Resurfacing is a separate service. It may be recommended when the membrane is still sound but its surface is worn. The maintenance inspection makes it possible to determine whether this type of work is relevant for your roof.
You can watch for signs that are visible from inside, such as stains on the ceiling. Going up on a roof involves risks, however, and a trained eye spots defects that easily go unnoticed. An inspection by a specialized roofer remains the safer choice.
To schedule preventive maintenance for your flat roof in Laval, call Toitures OBM at 514-449-5469, Monday to Friday from 8 a.m. to 5 p.m., or request a free quote.
OBM Roofing
Elastomeric membrane specialists for commercial, industrial and multi-unit buildings in Laval, Montreal and the North Shore.
