Blog
17 August 2026
Is your flat roof showing signs of wear? Are blisters appearing, is water pooling or are leaks showing up inside? It may be time to consider replacing your elastomeric membrane. In Brownsburg-Chatham, as everywhere in Quebec, freeze-thaw cycles, snow and UV rays wear down flat roofs, and a membrane at the end of its life can quickly cause damage to the insulation and the structure.
Here is what you need to know about commercial elastomeric membrane, the signs of wear to watch for and how a membrane replacement unfolds.
Elastomeric membranes are one of the most widely used waterproofing systems on flat roofs in Quebec. They are made of SBS modified bitumen, a bitumen to which polymers are added to give it great flexibility, even in cold weather. This flexibility helps the membrane follow the building’s movements and temperature changes without cracking.
It is installed as a two-ply system: a base sheet that provides the basic waterproofing, then a granulated cap sheet that protects the whole system from UV rays and wear. Depending on the building, the installation is torch-applied or done with self-adhered membranes.
Several factors shorten the lifespan of a membrane : a poorly executed initial installation, neglected maintenance, clogged roof drains or simply wear caused by the weather. It is therefore useful to know how to recognize the signs that a roof replacement is coming:
If you notice one or more of these signs, an inspection makes it possible to measure the extent of the damage.
A one-off repair may seem more economical in the short term, but it is not always the wisest solution. When the membrane is worn over a large area or repairs follow one after another, patching the holes one by one often means spending money without solving the underlying problem.
A roof replacement allows you to start over on a sound base. The old membrane is removed, the condition of the substrate and the insulation is checked, whatever needs fixing is corrected, and then a new two-ply elastomeric membrane is installed. Conversely, if the damage is localized, a repair or resurfacing may be enough: the inspection guides the choice, to avoid unnecessary work.
A roof replacement is the right time to evaluate the roof insulation. Wet or crushed insulation reduces the building’s thermal efficiency and promotes condensation, which speeds up wear on the membrane. Replacing damaged insulation at the same time as the membrane helps improve indoor comfort, summer and winter alike.
The work begins with a complete assessment: condition of the membrane, insulation, upstands, penetrations, roof drains and water drainage. This assessment makes it possible to accurately define the scope of the work.
The old membrane is removed, down to the substrate or the insulation depending on the condition of the materials. The surface is then cleaned, dried and prepared. Damaged insulation is replaced as needed.
The base sheet, then the granulated cap sheet, are installed according to the manufacturer’s specifications, torch-applied or self-adhered. Toitures OBM uses Soprema systems, for example conventional mechanically fastened or conventional self-adhered systems. The upstands, the areas around the roof drains and the penetrations receive special attention, because that is often where leaks begin.
Once the roof replacement is complete, preventive maintenance helps protect the investment. An inspection in the spring, after the snow melts, and in the fall, before the deep cold, makes it possible to quickly spot any anomaly.
Also make sure that the roof drains and overflows stay free of leaves and debris. Efficient drainage reduces the risk of water building up on the roof. With regular maintenance, an elastomeric membrane can protect a building for several decades.
Toitures OBM is a roofing contractor specializing in elastomeric membrane flat roofs, located at 1215 Tellier Street in Laval. Its service area extends from Lachute to Repentigny and from Sainte-Adèle to Montreal, which includes Brownsburg-Chatham as well as Lachute and Saint-Jérôme. The team offers elastomeric roof replacement, new flat roof construction, repair, resurfacing, and maintenance and inspection for commercial, industrial and multi-unit buildings, as well as for residential flat roofs.
Toitures OBM is Soprema PAQ+S certified and CAA-Québec Recommended, and holds RBQ licence 5778-2823-01. Its recommendations are clear and explained. Financing is available through Financeit.
It depends on the condition of the existing membrane and the insulation. If the old membrane has come loose or the insulation is wet, they must be removed. If the membrane is sound and only the surface is worn, resurfacing may be considered. The inspection makes it possible to decide.
A roof replacement replaces the waterproofing system, and often part of the insulation. Resurfacing keeps the existing membrane: it is cleaned, prepared and a new cap sheet is applied.
Requirements vary from one municipality to another. Check with your municipality before the work begins.
An elastomeric membrane replacement protects your building, preserves the insulation and the structure, and saves you from repeated repairs. To have your roof assessed, contact 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.
