Shingle roofing in Laval

A few shingles to change, or the whole roof?

As long as the defect is in one spot, it is a matter of roof repair. A few shingles blown off, a shifted chimney flashing, a cracked vent boot, a popped nail: we redo the area without touching the rest of the slope.

The condition is that the surrounding shingles are still flexible. To slip in a new piece, the ones covering it must be lifted. Shingles that crack when bent signal a roof at the end of its life, where every repair damages what surrounds it.

When the same defects show up from one slope to the next, it is the replacement that needs a quote.

What Laval means by a sloped roof

For Laval's Code de l'urbanisme (urban planning code), any roof with a pitch greater than 2:12, or 16.7%, is sloped. At 2:12 or less, the Code calls it a flat roof. Manufacturers also set a minimum slope for their shingles, and a roof with too little pitch calls for another roofing.

The City writes that most of its urbanized territory is occupied by single-family homes, businesses and industries of one or two storeys. According to its 2024 figures, single detached houses make up 42% of dwellings, and semi-detached or row houses, 11%. These documents say nothing about the shape of roofs.

Shape, however, changes the job. Two or four simple slopes are covered quickly. A cut-up roof, with valleys, dormers and different levels, takes more time.

Seven parts that work together

The shingles are the part you see. Watertightness depends on the whole assembly.

1. The deck. Wood boards or panels fastened to the framing, the support for everything else.
2. The drip edge. A metal edging that sends water into the gutter.
3. The eave membrane. A self-adhesive strip at the bottom of the slopes, in the valleys and around openings.
4. The underlayment. Felt or a synthetic membrane, over the rest of the deck.
5. The shingles. They start from a starter strip and rise in overlapping courses.
6. The flashings. Bent metal at the joints with the chimney, walls, dormers and vents.
7. The ventilation. Air enters through the soffits and exits near the ridge. The attic stays cold and dry.

Five weak spots to watch

Water often gets in where the roofing stops or changes direction, more than in the middle of a slope.

• The hollow between two slopes. The valley takes water from both sides and holds snow and leaves.
• The chimney. Masonry moves and crumbles, and the flashing has to follow it.
• Pipes and vents. The rubber seal of a plumbing boot dries out in the sun, then cracks.
• The base of a wall. Under a dormer or an upper storey, water runs along the wall before coming back down.
• The roof edge. In winter, ice settles there and water can back up under the first courses.

We start our inspection at these spots.

The replacement job, from the bin to the magnet

1. Prepare the property. Tarps cover the flower beds and the driveway, then the bin arrives.
2. Tear off. The old shingles and underlayment come off, down to bare wood.
3. Examine the wood. Any rotten or sagging section is replaced before going further.
4. Weatherproof the roof. Drip edge, eave membrane and underlayment go on, and a shower no longer does damage.
5. Install the shingles. One course after another, with the flashings, vents and ridge.
6. Clean up. The debris goes, then a magnet picks up the nails.

No one knows the condition of the deck before the tear-off. Have the billing for replaced wood written down in advance, and stay reachable that day.

A careful contractor only uncovers the area they can cover again the same day. Ask what they plan to do if rain arrives mid-job.

On a house with a simple roof, this job is counted in days rather than weeks, and the planned duration is written in the quote.

Reading a quote line by line

Two prices can only be compared if both documents describe the same work.

• How far the tear-off goes. Down to the wood, and on every slope?
• The wood. How replaced decking is measured and billed.
• The product. The manufacturer, the exact product line and the colour.
• What goes underneath. Which underlayment, and where the eave membrane will go.
• The metal. The flashings redone new and those kept, especially at the chimney.
• The ventilation. The planned vents, and the condition of the soffit air intakes.
• The two warranties. The manufacturer's for the product, the roofer's for the installation, each with its duration.
• The logistics. Protection of the property, the bin, the cleanup and the dates.

Why two roofs of the same size do not cost the same

• The actual roof area, which exceeds the house's footprint when the slope is steep.
• The slope and height, which dictate the safety equipment and slow the installation.
• Valleys, dormers, chimneys and skylights, which add detail work.
• The number of layers of old shingles to tear off.
• The shingle line chosen.
• The wood to replace and the ventilation to correct.
• Access for the bin and the delivery.

Laval's rules for a sloped roof

The permit. For a residence, the City's page on exterior renovation separates two cases. Replacing the roofing with the same material requires no permit. Replacing it with a new material requires one. The City does not define what it means by the same material. When in doubt, the Service de l'urbanisme (the City's urban planning department) answers before the work.

Materials. Article 379 of the Code de l'urbanisme sets a closed list of roofing materials. Among those installed on a sloped roof, it includes:

• asphalt, aluminum, enamelled or textured steel, wood or fibreglass shingles
• factory-painted and pre-baked metal
• clay, slate or fibreglass tile
• plastic or recycled tire tile
• galvanized sheet metal, standing seam, batten seam or Canadian-style
• copper
• composite roofing

The same chapter of the Code lists asbestos shingles among prohibited materials. An old, rigid and brittle shingle that no one can identify must not be handled: leave it in place and mention it in your request.

Article 380. This article of the Code requires, for a flat-roofed building, a green roof, a white covering or a material with a solar reflectance index of at least 78. Article 380 does not apply to sloped roofs. The Code does not specify what applies to an existing flat roof redone identically.

Heritage. In a territory of heritage interest, changing the roofing materials of a principal building goes through a PIIA (site planning and architectural integration program). The Code exempts three cases: replacing a material with the same material in a similar colour, replacing it with a material that keeps or restores the original or traditional features, and renovating a flat roof. The same rule applies to a building of heritage interest, wherever it is. Outside these cases, the City may ask for the project to be submitted to it, and it decides. The City's Info-règlements tool shows, for an address, the special provisions of its zone.

The contractor. In Quebec, a construction contractor must hold a licence from the Régie du bâtiment du Québec (RBQ, Quebec's building authority). Its public register can be checked before signing.

Frequently asked questions