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Photo of a person waterproofing a roof

Flat roofs don’t drain the same way as sloped roofs. That said, both types of roofs must be properly waterproofed to prevent water infiltration and moisture problems. At René Perron Couvreurs in Montreal and Laval, we specialize in installing and repairing flat roofs. Keep reading to learn more about how flat roofs can be waterproofed.


Flat roofs are only slightly pitched. This limits the type of coverings that can be applied to provide adequate weather protection. In general, flat roofs consist of a load-bearing element and a vapour barrier, as well as a substrate, coating and waterproofing protection. The latter two elements depend on the type of roof.


Asphalt and gravel roofs consist of about four or five layers of felt covered with liquid asphalt and fine gravel. The layered felt ensures the roof is watertight, while the gravel protects it from damaging ultraviolet rays and inclement weather. This multi-layered roof is durable and has a lifespan of over 25 years.


Elastomeric membranes are made of two layers fused together with a blowtorch to ensure moisture resistance. One layer contains granules to increase durability and protect the roof from ultraviolet rays and extreme weather. Robust and esthetic, elastomeric membranes can be placed over existing asphalt roofs.

At René Perron Couvreurs, we offer IKO elastomeric membranes. Made of modified bitumen, they can also be used in two-layer waterproof and watertight installations.


Single-layer TPO membranes (thermoplastic polyolefin) are made of rubber and other synthetic materials. They’re mechanically fastened and don’t require an open flame to provide protection against ultraviolet radiation, bacteria and extreme weather. TPO membranes are ideal for large roofs but not ventilated roofs.


Choosing the best type of roof covering to ensure a waterproof seal depends on various factors. These include the pitch of the roof, the surface area and the number of features like vents and chimneys, which must be bypassed during installation. Using top-of-the-line products for the vapour barrier, insulation panels and eave protection will optimize the performance and water tightness of your roof.

Do you need a new covering for your flat roof in Laval or the surrounding area? At René Perron Couvreurs, we’ve been maintaining and repairing roofs for over 90 years. Contact us today to learn more about our services.


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