Alberta · Wildfire guide

Fire-resistant roofing, Alberta

A Class A fire-rated roof assembly gives a house, acreage or cabin the best protection from embers, and the roof covering itself should be something that does not burn. This guide covers what the ratings mean, how the common roofing materials compare, and the FireSmart steps that matter most in Alberta, from the company that has installed Interlock® roofs across the province since 1999.

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Fire rating

Class A Fire Rated Available, as a complete assembly

Two layers of GAF VersaShield® over 12 mm plywood, per ASTM E108.

The metal

Aluminum does not ignite

Embers that land on the roof have nothing to burn.

Embers

Carried up to 2 km ahead of a fire

FireSmart Canada. The roof is the biggest target on the house.

Why it matters in Alberta

Wildfire has burned into Alberta towns more than once in the last 15 years: Slave Lake in 2011, Fort McMurray in 2016 and Jasper in 2024. Each time it destroyed homes inside town limits, and in 2023 the province recorded more than 2.2 million hectares burned. The forest and grassland run right up to the towns, acreages and mountain communities where many Albertans live.

Alberta wildfires since 2011: what burned and what it cost
Year	Fire	Loss	What happened
2011	Slave Lake	374 properties destroyed	About one-third of the town burned in May 2011. Insurance Bureau of Canada put insured damage at about $700 million at the time.
2016	Fort McMurray (Horse River fire)	About 2,400 homes and buildings	More than 80,000 people evacuated. Insurance Bureau of Canada estimated insured damage at $3.58 billion, the costliest insured disaster in Canadian history.
2023	1,094 wildfires province-wide	2,214,957 ha burned	About ten times the area of the five-year average. More than 38,000 Albertans were evacuated from 48 communities.
2024	Jasper	358 of 1,113 structures in the townsite	About one-third of the town's buildings were lost. Insurance Bureau of Canada's estimate of insured losses reached close to $1.3 billion, the second-costliest wildfire in Canadian history.

Sources: Insurance Bureau of Canada figures reported by CBC News for Slave Lake and Fort McMurray; CBC News for Slave Lake properties; Government of Alberta figures reported by Lethbridge News Now for 2023; Parks Canada via CBC News and Insurance Bureau of Canada for Jasper. Full list at the end of this page.

Acreages, mountain towns and the north

We roof homes across Alberta, from Calgary and Edmonton to acreages in the foothills, Canmore and the Bow Valley, Hinton and Whitecourt, and north to Grande Prairie, Slave Lake and Fort McMurray. A house in the trees has the same weak points as any house in a wildfire (the roof, the gutters, the vents, the deck), and on an acreage or in a mountain town there may be fewer people around to notice a spot fire and a longer wait for help.

FireSmart's advice is the same for a city lot and an acreage: start at the roof, work down the outside walls, then move out through the three zones around the building. To report a wildfire in Alberta, call 310-FIRE (3473), toll free, 24 hours a day. If people or buildings are in danger, call 911.

How a house catches fire in a wildfire

Many houses lost to wildfire are never touched by a wall of flame. They catch from embers: burning bark, needles and debris carried by the wind, which FireSmart Canada says can travel up to two kilometres.

Embers settle where debris collects: in gutters and roof valleys, against vents, in gaps at the eaves and on decks. A roof covering that burns, or a roof full of dry needles, gives them fuel. That is why the roof, and everything around its edges, is the first thing to get right.

What Class A, B and C actually mean

Roof fire ratings come from ASTM E108 (also published as UL 790) and its Canadian counterpart, CAN/ULC-S107. The tests expose a roof sample to fire from outside the building: a flame spreading across the surface, burning wood brands dropped on it, and repeated bursts of flame. The rating belongs to the assembly that was tested, meaning the covering, the underlayment and the deck together. Change one layer and the rating may not hold.

Class A

Severe fire exposure

Maximum flame spread: 1.8 m (6 ft)
Burning brand test: One 30 cm (12 in) brand, about 2,000 g
Intermittent flame: 15 cycles

The rating FireSmart Canada says offers the best protection.

Class B

Moderate fire exposure

Maximum flame spread: 2.4 m (8 ft)
Burning brand test: Two 15 cm (6 in) brands, about 500 g each
Intermittent flame: 8 cycles

Better than C, not the choice for a house or cabin in the forest.

Class C

Light fire exposure

Maximum flame spread: 4.0 m (13 ft)
Burning brand test: Twenty 4 cm (1.5 in) brands, about 9 g each
Intermittent flame: 3 cycles

Not recommended where wildfire or nearby structure fires are a risk.

Roofing materials compared for fire

Typical classifications as tested. Any one product can differ, so ask for the product's fire listing and the assembly it was tested on.

Typical fire classification of common roofing materials
Material	Typical fire classification	What to know
Untreated cedar shakes and shingles	Commonly unrated	FireSmart Canada: untreated wood shakes are a dangerous combination of combustible material and crevices where embers and sparks collect.
Fire-retardant-treated cedar	Class B or C; some Class A as a tested assembly	The treatment can weather out over the years. Check the product's listing and age.
Asphalt shingles (fibreglass)	Commonly Class A	Fibreglass-mat shingles are usually Class A. The roof still has to be kept clear of needles and leaves, which can ignite on top of it.
Clay and concrete tile	Commonly Class A	Non-combustible, but heavy, and the gaps under the tile need ember-resistant closures at the eaves and ridge.
Natural slate	Commonly Class A	Non-combustible and heavy; the roof structure has to be built for the weight.
Synthetic and rubber composite	Varies by product	Some products reach Class A only with a specific underlayment. Read the listing, not the brochure.
Interlock® aluminum	Class A Fire Rated Available as a complete assembly	Two layers of GAF VersaShield® over 12 mm (15/32-inch) plywood, per ASTM E108. Aluminum itself does not ignite.

The Interlock® roof, built as a Class A assembly

Interlock® roofs are heavy-gauge aluminum, made in Canada by Interlock Roofing Ltd. at its plant in Delta, BC, and installed in Alberta by our own Alberta company. Class A Fire Rated Available as a complete assembly: two layers of GAF VersaShield® fire-resistant underlayment over 12 mm (15/32-inch) plywood, per ASTM E108. CAN/ULC-S107 is the matching Canadian test standard.

The panels weigh roughly 2 to 3.5 kg per square metre depending on profile, a fraction of tile or slate. Every profile (Slate, Cedar Shingle, Shake, Mediterranean Tile and Standing Seam) needs a minimum 3/12 roof slope.

If your house, acreage or cabin backs onto forest, tell us at the estimate. We price the Class A assembly and walk the whole roof edge with you: gutters, vents, eaves and anywhere embers could collect.

Product engineering and test reports are the manufacturer's to explain: interlockroofing.com ↗

Beyond the roof: FireSmart your property

Alberta uses the national FireSmart Canada program, and FireSmart Alberta publishes its own guidance for homeowners. Both divide the land around a building into three zones, and the closer to the house, the more it matters. FireSmart Alberta's roof fact sheet lists asphalt-composition shingles, metal, and slate, clay or concrete tile as Class A options.

Immediate zone · 0 to 1.5 m

The house and a non-combustible strip around it. This is where embers reach the roof, gutters, vents, decks and anything stored against the walls, and every inside corner of the roof is a place where debris and embers collect.

Intermediate zone · 1.5 to 10 m

Reduce shrubs, evergreen trees and dead material within 10 metres of buildings, and move firewood, sheds and fuel away from the house.

Extended zone · 10 to 30 m

Thin and prune trees within 10 to 30 metres of the house, and clear dead material, so a fire coming through the lot drops to the ground.

Roof and roof-edge checklist

Choose a Class A roof assembly. Ask your roofer what the assembly is, not just the panel.
Keep the roof and gutters clear of needles and leaves, and choose non-combustible gutters and gutter guards.
Fit non-combustible vents with 3 mm metal screening, as the FireSmart Home Ignition Zone self-assessment recommends, to keep embers out of the attic.
Close open eaves and the gaps at the ridge and roof edges where embers and debris collect, including every inside corner of the roof.
Keep skylights and solar panels clear of debris; FireSmart Alberta notes they can collect wind-blown embers.
Enclose the underside of decks and porches, and don't store anything combustible on or under them in fire season.

The FireSmart Home Ignition Zone self-assessment, published on the Government of Alberta's open data site, walks you through your own property. Your municipality or local fire department can tell you about fire bans and burn permits where you live.

Fire-resistant roofing: questions, answered

What is the most fire-resistant roofing material?

Non-combustible coverings such as metal, clay or concrete tile and natural slate, installed as a Class A assembly. Under ASTM E108 and CAN/ULC-S107 the fire classification belongs to the whole assembly (covering, underlayment and deck), so the same covering can rate differently on a different build-up. On our roofs, Class A Fire Rated Available as a complete assembly: two layers of GAF VersaShield® over 12 mm plywood.

Is a metal roof fire resistant?

Aluminum does not ignite, so embers landing on it have nothing to burn. The fire rating, though, is for the assembly: Interlock® roofs have Class A Fire Rated Available as a complete assembly, with two layers of GAF VersaShield® over 12 mm (15/32-inch) plywood, per ASTM E108.

What is a Class A fire-rated roof assembly?

A roof assembly that passed the most severe of the three fire tests in ASTM E108 (UL 790) or its Canadian counterpart, CAN/ULC-S107: flame spread of no more than 1.8 m (6 ft), a 30 cm burning brand of about 2,000 g without the deck igniting, and 15 cycles of intermittent flame. Class B and C use smaller brands and allow more spread.

What roofing does FireSmart Alberta recommend?

FireSmart Alberta's roof fact sheet says Class A fire-rated roofing provides a high level of protection and lists asphalt-composition shingles, metal, and slate, clay or concrete tile as Class A options. It also says to clean leaves and needles off the roof regularly and to repair curling or damaged shingles.

Are cedar shakes a fire risk?

Untreated cedar shakes are commonly unrated, and FireSmart Canada describes untreated wood shakes as a dangerous combination of combustible material and crevices where embers collect. Treated shakes do better, but the treatment can weather out.

Does a metal roof make my house fireproof?

No roof does, and no honest roofer will say so. A Class A assembly and a covering that does not ignite take away the largest ember target on the house. Clear gutters, screened vents, a non-combustible strip around the walls and managed trees do the rest.

Do I need a Class A roof assembly in Alberta?

It depends on the building and where it is, so check with your municipality's building or fire department before you start; some Alberta communities have their own FireSmart rules. Where it isn't required, FireSmart Canada still says a Class A fire-rated roof assembly offers the best protection, and that matters most for homes, acreages and cabins in or beside the forest.

Is my acreage or mountain home at risk from wildfire?

Any building in or beside the forest or grassland can be reached by embers, which FireSmart Canada says can travel up to two kilometres. Acreages and cabins are often at the end of long roads with limited water and a longer wait for help. Start at the roof, then work down the walls and out through the three FireSmart zones.

Will a fire-resistant roof lower my insurance?

Each insurer sets its own rates and rules, so ask yours directly and get the answer in writing. A new roof with a documented Class A assembly is something you can show your insurer.

Who do I call to report a wildfire in Alberta?

Call 310-FIRE (3473), toll free, 24 hours a day, to report a fire you see in a forested area. If people or buildings are in danger, call 911.

Can you install the Class A assembly on my house or cabin?

Yes, in Alberta. Tell us at the estimate that you want the Class A assembly priced, and we'll walk the whole roof edge with you: gutters, vents, eaves and anything else embers could reach. Call (587) 317-6517 or book a free consultation.

Sources

Figures are as published by each source on the date noted. Page reviewed October 2026.

Get the Class A assembly priced.

A fixed price in writing after one visit. Interlock Metal Roofing (Alberta) Ltd. · 210, 3750 46 Ave SE, Calgary, AB T2B 0L1