Metal Roofing in Montreal

Types of metal roofing

"Metal roof" covers very different products. They do not look the same, are not installed the same way and do not allow the same pitches.

Standing seam. The panels run from the bottom to the top of the slope, with no visible screws. Their edges turn up and lock together to form a rib, then the seam is crimped by hand or by machine. Hidden clips under the seam hold the metal to the deck. This is the metal of contemporary-looking roofs and of many heritage buildings.

Ribbed or corrugated panels. The panels are screwed through the metal, with screws fitted with a sealing washer. You see them on garages, sheds, farm buildings and more and more houses. The exposed screws are the thing to watch over the years.

Steel shingles and tiles. Small stamped panels imitate shingles, slate or tile. Some are coated with stone granules. They give the look of a traditional roof with the lifespan of metal.

Steel or aluminum

Most metal roofs are steel. The steel first gets a metallic coating that protects it from rust, then a factory-baked paint. Vicwest's UltraVic sheet (February 2024) offers two coatings: galvanized, a zinc layer, or an aluminum-zinc alloy.

Aluminum does not rust. It is lighter than steel and softer. It dents more easily under hail or a block of ice.

Metal does not get along with every other metal. One steel tile manufacturer's installation guide forbids lead and copper in contact with its panels. On an old Montreal house, copper flashing or an old eavestrough is therefore settled in the quote.

Minimum pitch

The pitch decides which type of metal roofing is allowed. Manufacturer sheets set it, product by product.

• Screw-down panels. Vicwest's UltraVic sheet, an exposed-fastener panel, requires a pitch of at least 3:12.
• Steel shingles and tiles. The TAMKO and DECRA installation guides require at least 3:12. According to DECRA's guide, below 3:12 its panels become decorative and must sit on a roofing system that is watertight on its own.
• Mechanically seamed standing seam. Some systems go much lower. A Sheffield Metals sheet (2021) gives 0.5:12 for steel and 2:12 for aluminum, with in-seam sealant below 2:12.

According to the City of Montreal, a roof with a pitch under 2:12 is a flat or low-slope roof. When a flat roof is redone, most boroughs require a white roof, a reflective material or a green roof. Metal installed below 2:12 must therefore also meet your borough's flat roof rules.

Snow and ice

Snow slides off metal. That is an advantage for the load on the roof and a risk on the ground. A slab that lets go all at once can land on a doorway, a sidewalk, a car or the neighbour's yard.

Snow guards hold the layer on the roof so it melts in place. On standing seam, the brackets are often clamped to the seams, without piercing the metal. We place them above doors, walkways and parking spots. On the tight lots of the island, their location is decided in the quote.

The RBQ writes that ice and icicles at the edge of a building are a danger to pedestrians and cars. As long as a slab of snow threatens to slide, mark off the area below and stay on the ground.

Condensation, underlayment and ventilation

Humid air that touches the underside of cold metal condenses into drops. On a house, the underlayment catches that water and keeps it away from the wood. DECRA's guide requires an underlayment under all its products, in new construction and in reroofing. TAMKO's guide requires an underlayment over the whole deck for pitches from 3:12 to 4:12.

Attic ventilation matters as much under metal as under shingles. TAMKO's guide states that inadequate attic ventilation can cause condensation and ice dams. Before installing the metal, we look at the air intakes at the soffits and the exhausts near the ridge.

Noise in the rain

Metal on a shed rings in the rain. It is screwed to strapping there, with nothing underneath. On a house, the metal usually sits on a solid deck and an underlayment, above an insulated attic. The sound of rain is well dampened.

Installing metal over an old roof

Some steel shingles go over existing asphalt shingles. The TAMKO and DECRA guides allow it, with specific preparation at the roof edges. You then see neither the deck nor the underlayment. The roof also carries extra weight.

Before covering over, we check the condition of the deck and the moisture in the attic. When the wood is doubtful, we recommend tearing off down to the deck. Our written quote states which of the two methods we propose for your roof.

Permits and rules in Montreal

The City of Montreal states that, in most cases, a permit is needed to replace the roofing on a sloped roof. Rules vary by borough, type of building and nature of the work. In some boroughs, replacing the roofing with a similar material needs no permit, but changing material does. Going from asphalt shingles to metal is a change of material.

The list of allowed materials also changes from one borough to the next. According to the City's page, some forbid unpainted metal or non-architectural sheet metal. Others require a technical sheet with the solar reflectance index, even for a sloped roof. Buildings and areas of heritage value have additional standards on material, shape and colour.

Confirm with your borough's permit counter before you sign. Tell us if you want the technical sheet of the chosen metal attached to our quote.

What affects the price

Metal costs more to install than asphalt shingles. The price of a metal roof varies with:

• the type of metal roofing: standing seam, screw-down panels or steel shingles
• the metal, the gauge and the paint chosen
• the real roof area, larger than the footprint when the pitch is steep
• the shape of the roof: valleys, dormers, chimneys and skylights need custom-formed pieces
• the tear-off of the old roofing and the wood to replace underneath
• snow guards, flashing and ventilation corrections
• the height of the building and access for delivering the panels

Why trust us with your metal roof

We hold a licence from the Régie du bâtiment du Québec and have over 20 years of experience. We carry civil liability insurance. We install metal roofing and we are the most qualified to see your project through.

We come and look at the roof before pricing it. Our written quote is detailed, free and with no obligation. It specifies the type of metal roofing, the metal, the underlayment, the flashing, the snow guards and the ventilation. Our warranties are provided in writing. If the metal tears off or leaks in the middle of a storm, we answer emergencies 24 hours a day, 7 days a week.

Ask us for our licence number and check it in the RBQ's public register, as you would for any contractor.

Frequently asked questions