Flat Roofs in Terrebonne: Roofers and Advice

In Terrebonne, most houses in Lachenaie, La Plaine and the Terrebonne sector have sloped asphalt-shingle roofs. Flat roofs are found elsewhere: on duplexes and triplexes, apartment buildings, additions and attached garages, and on the businesses along Boulevard des Seigneurs and Boulevard Moody. Redoing a flat roof is a different trade from installing shingles, and not every roofer does it.

This guide covers what to know before calling a roofer for a flat roof in Terrebonne, then lists the companies in the city whose listing says they install membranes.

The Four Types of Flat Roofs

A flat roof is never completely flat: it has a slight slope toward the drains. What changes from one roof to another is the membrane that keeps it watertight.

• Elastomeric membrane (SBS modified bitumen). Installed in two torch-welded plies, it is the most common on plexes and houses in Quebec. It often lasts 25 to 35 years.
• TPO membrane. A single-ply white membrane, welded with hot air. It reflects heat and is mostly seen on commercial and newer buildings. Expect 20 to 30 years.
• Built-up roofing (tar and gravel). The older method, with several layers of felt and asphalt covered in gravel. It lasts 15 to 25 years and is now mostly replaced with elastomeric.
• EPDM. A rubber membrane, less common on houses, seen on some additions and commercial buildings.

Signs a Flat Roof Needs Redoing

A flat roof cannot be seen from the street. Problems are often noticed too late, from inside. Go up on the roof (or have it inspected) in spring and fall, and watch for these signs:

• water that stays in puddles more than 48 hours after rain;
• blisters, cracks or a membrane lifting at the edges;
• displaced gravel leaving the built-up roof exposed;
• flashing (the metal strips around parapets and chimneys) that is loose or rusted;
• a water stain on the top-floor ceiling, especially after snowmelt.

A membrane past its lifespan does not repair well. In that case, a roofer will often suggest replacing your roof entirely rather than piling up repairs.

Winter on a Flat Roof

Snow weighs more on a flat roof than on a sloped one, because it does not slide off. After a big storm or rain on snow, the load can become significant. Several roofers in the area offer flat roof snow removal in winter. Drains must stay clear: a drain blocked by ice pushes water up to the flashing, and that is where it gets in. Ice dams mostly affect sloped roofs, but the principle is the same: meltwater that cannot drain eventually finds a way in.

Before You Sign

The licence. The roofer must hold a Régie du bâtiment du Québec licence covering roofing work (subcategory 7: insulation, waterproofing, roofing and siding). You can verify an RBQ licence in seconds with its number.

The permit. Most cities require a permit or authorization certificate to redo a roof, even with the same materials. Check with the City of Terrebonne before work begins. Some cities also require a light-coloured or reflective covering when a flat roof is redone.

The quote. A serious quote states the type and brand of membrane, the number of plies, the insulation (if replaced), the flashing, the drains and both the manufacturer's and the installer's warranties. When comparing contractor quotes, line these items up side by side: two very different prices almost always hide two different jobs.

Flat Roof Roofers in Terrebonne

The companies below are Terrebonne roofers whose Zone Réno listing says they work with membranes (elastomeric or TPO). Ask each one which type of flat roof they redo most often, and for examples of work similar to yours.

Frequently Asked Questions

How long does a flat roof last?

It depends on the membrane. An elastomeric membrane often lasts 25 to 35 years, a TPO membrane 20 to 30 years, and built-up roofing 15 to 25 years. Maintenance, clear drains and good ventilation extend that lifespan.

Can a new membrane go over the old one?

Sometimes, over a membrane that is still sound and dry, but the manufacturer does not always allow it and it is not always advisable. If the insulation underneath is wet, everything has to come off. A roofer should check the roof's condition before suggesting it.

Do I need a permit to redo a flat roof in Terrebonne?

Most cities require a permit or authorization certificate for roofing work. Check with the City of Terrebonne before starting, and ask the roofer whether they handle the application.

Which membrane is best for a residential flat roof?

Elastomeric is the most common choice on houses and plexes in Quebec: it is durable and most roofers know it well. TPO is more common on commercial buildings and large surfaces. The right choice also depends on roof access, insulation and your budget.