Blog
6 April 2026
Is your flat roof in Sainte-Adèle leaking again, or is the membrane showing signs of wear all over? Before repairing it one more time, it is worth asking whether the time has come to redo the roof. A flat roof replacement replaces the existing covering with a new two-ply elastomeric SBS modified bitumen system.
This article helps you recognize the signs that lead to a roof replacement, tell it apart from a repair or resurfacing, and know what it includes.
A flat roof does not deteriorate overnight. The signs build up over the years, and it is often their combination that shows a roof replacement is becoming the most sensible solution.
An isolated leak can be repaired. When leaks keep coming back in different places, season after season, it is often because the membrane has lost its watertightness over a large area. Each repair fixes one spot, but another one appears elsewhere.
Numerous blisters, cracks, loose sections, missing granules that leave the bitumen exposed: when these defects cover a good part of the roof, the membrane is reaching the end of its life.
If water stays in place for several days after a rain, the membrane ages faster in those spots. A roof replacement is an opportunity to review the roof drain connections and water drainage.
When water has been seeping in for a long time, the insulation under the membrane can become wet. It then loses its effectiveness and can damage the membrane above it. This problem cannot be solved with a surface repair.
Some signs can also be seen from the inside: stains or rings on the top-floor ceiling, blistering paint, a musty smell. However, water can travel along the insulation or the roof deck before showing up, so the location of the stain does not always match that of the leak.
Not every worn flat roof needs a roof replacement. Toitures OBM’s approach is to assess the condition of the roof and the needs of the building before recommending anything, to avoid unnecessary work. Here is how the three options differ:
Each recommendation is clearly explained to the owner, along with the reasons behind it.
A roof replacement follows a structured method. The details vary from building to building, but the main steps are the same.
The old membrane is removed to expose the substrate. This step reveals the actual condition of the roof beneath the surface. The debris is then picked up and the substrate is cleaned before the work continues.
Wet or damaged insulation is replaced. If the roof deck has a problem, the owner is informed before the work continues.
The base sheet, then the granulated cap sheet, are torch-applied or installed in a self-adhered version, depending on the chosen system. Toitures OBM works with Soprema systems, including the mechanically fastened conventional system and the self-adhered conventional system.
The roof drains are connected to the new membrane, the upstands are redone along parapets and walls, and every penetration is sealed. These are the most sensitive spots on a flat roof. At the end of the project, the roof is inspected one last time and the roof drains are checked.
Membrane work requires dry conditions, and the period from spring to fall is the most suitable. Having the roof assessed at the first signs of wear leaves time to plan the roof replacement at the right moment, rather than waiting for a leak to force the decision. For permits, check with your municipality.
For owners who want to spread out the cost, financing is available through Financeit.
Toitures OBM is a roofer specializing in elastomeric membrane flat roofs, based at 1215 rue Tellier in Laval. Its service area stretches from Sainte-Adèle to Montreal, which includes commercial buildings, apartment buildings and flat-roof houses in Sainte-Adèle.
Toitures OBM is Soprema PAQ+S certified, CAA-Québec Recommended and holds RBQ licence 5778-2823-01.
When the membrane is still sound, resurfacing can extend its life. When it is at the end of its life or the insulation is wet, the old covering should instead be removed to fix the problem at the source.
There is no set number. If leaks keep coming back in several places and the membrane is worn over a large area, an inspection will show whether a roof replacement makes more sense than further repairs.
An inspection in spring and fall, with roof drain cleaning and a check of the seams, upstands and penetrations, helps the new membrane last several decades.
To have your flat roof assessed in Sainte-Adèle, contact the Toitures OBM team Monday to Friday, from 8 a.m. to 5 p.m., at 514-449-5469, or request a free quote.
OBM Roofing
Elastomeric membrane specialists for commercial, industrial and multi-unit buildings in Laval, Montreal and the North Shore.
