Blog
28 September 2026
A flat roof doesn’t always show its weaknesses. In Boisbriand, as elsewhere on the North Shore, many owners of apartment buildings, commercial buildings or plexes only discover a roofing problem when a stain appears on the ceiling. Flat roof maintenance and inspection are meant to catch these weaknesses before they turn into water infiltration.
The Quebec climate puts a membrane to the test: freeze-thaw cycles, snow buildup, mild spells, heavy spring rain and UV rays in summer. Regular follow-up helps extend the life of the roof and plan the work at the right time, rather than having to deal with it in a hurry.
From the ground, a flat roof can look like it’s in good shape while the membrane is deteriorating. Seams come loose, cracks appear on the surface and the roof drains gradually clog. Water eventually finds a way in and slowly seeps into the building.
Water damage often goes beyond the roof itself. A leak can soak the insulation, which then loses its effectiveness, and can encourage mould and damage ceilings and interior finishes. In an apartment building, it also affects tenants. Regular inspection reduces the risk of a small defect turning into major work.
The inspection begins with an examination of the entire surface of the elastomeric membrane: cracks, blisters, loose sections, areas where the surface granules have worn away, and spots where water stays after the rain. These observations make it possible to judge whether the membrane is aging normally or whether certain areas need attention.
On a flat roof, water must flow to the roof drains without pooling. Leaves, debris, sand and dirt eventually clog the strainers and the drains. Standing water puts constant pressure on the membrane and seeks out the slightest weakness. Maintenance includes cleaning the roof drains and checking drainage, especially before winter and after the snow melts.
Junction points are the most sensitive areas of a flat roof: upstands along walls and parapets, flashings, plumbing vents, ventilation ducts, mechanical equipment bases and skylights. With freeze-thaw cycles, these details move more than the rest of the surface. Checking them systematically makes it possible to spot an open seam or a loose section before it lets water through.
Some areas aren’t causing problems yet but show signs of wear. Identifying and noting them makes it possible to track how they evolve from one inspection to the next. When a spot repair is justified, such as resealing around a roof drain or a penetration, it can be planned without waiting for a leak to occur.
For most buildings, two inspections a year is a good benchmark: one in spring, after the snow melts, to see the effects of winter, and one in fall, before the first cold snap, to make sure the roof drains are clear and the seams are in good condition.
An additional inspection is useful after a major storm, after work on the roof such as installing mechanical equipment, or as soon as something unusual appears: a damp stain on the ceiling, a blister on the membrane, or water that stays on the surface for several days after the rain.
An inspection also helps you make informed decisions. When the membrane is in good overall condition, regular maintenance and a few localized repairs are often enough. When the surface is worn but still sound, resurfacing, which means cleaning and preparing the existing membrane and then applying a cap sheet, can extend its life. When leaks keep coming back or the insulation is wet, an elastomeric roof replacement becomes the solution to consider.
Keep a record of every inspection and every repair. This history helps you track how the roof is evolving and plan the building’s maintenance budget over several years.
A properly installed elastomeric membrane that is maintained regularly can last several decades. On the other hand, a neglected roof may need to be redone sooner than expected. Maintenance also helps keep the insulation dry, preserving its thermal efficiency through long winters.
For a building owner, regular follow-up also makes management easier: fewer surprises, work planned at the right time and tenants less exposed to water damage.
Toitures OBM specializes in elastomeric membrane flat roofing, namely two-ply SBS modified bitumen systems that are torch-applied or self-adhered. The company, located at 1215 rue Tellier in Laval, works in Boisbriand and elsewhere on the North Shore, as well as in Laval and Montreal, on commercial, industrial and multi-unit buildings and on residential flat roofs.
Before recommending anything, the Toitures OBM team assesses the condition of the roof and the needs of the building to avoid unnecessary work, then clearly explains its recommendations. The company is Soprema PAQ+S certified, CAA-Québec Recommended and holds RBQ licence 5778-2823-01.
Yes. Most leaks start with a small defect that can’t be seen from inside: an open seam, a partially clogged roof drain or a loose section of membrane. The inspection is meant to find them before water reaches the insulation and the ceilings.
Leaves and debris build up mostly in the fall. A roof drain that is clogged when the first frosts arrive can keep meltwater from draining, which leads to ice and water accumulating on the membrane.
A quick look to check that a roof drain isn’t clogged is possible when access is safe. A full inspection of the seams, upstands and membrane, however, requires the eye of a specialized roofer who knows how to recognize signs of wear and avoid damaging the membrane while walking on it.
A well-monitored flat roof brings fewer surprises and is easier to plan for. To have your flat roof inspected or maintained in Boisbriand, contact the Toitures OBM team at 514-449-5469, Monday to Friday from 8 a.m. to 5 p.m., or fill out the form to get a free quote.
OBM Roofing
Elastomeric membrane specialists for commercial, industrial and multi-unit buildings in Laval, Montreal and the North Shore.
