Cold is not the enemy. Cycling is.
Roofing materials rarely fail because a January night hit minus thirty. They fail from being moved: expanded by sun, contracted by cold, soaked, frozen, thawed and soaked again, a few hundred times a year. Windsor and Halifax cross the freezing point far more often than Yellowknife does, which is why a roof in southern Ontario or on the Atlantic coast can age faster than one in the territories despite much milder winters.
Add the second Canadian variable, snow load, and the shortlist of materials that make sense here gets short quickly.
Asphalt shingles
They cover the overwhelming majority of houses in the country, and for ordinary sloped roofs they remain a sensible default. Two formats are sold: three-tab, which is a single flat layer, and laminated or architectural shingles, which bond two layers together for thickness, a deeper shadow line and considerably better wind and tear performance. The price gap between them is small relative to the cost of the job, and in most of Canada there is little reason to choose three-tab on a house anymore.
What to know about them in this climate:
- They rely on a heat-activated sealant strip to bond each course to the one below. Install in a cold snap and that strip may not set until the following spring, leaving the roof vulnerable to wind in the meantime. Good crews hand-seal when working late in the season.
- Asphalt gets brittle below roughly minus five, so cold-weather work needs care in handling and nailing.
- Wind resistance depends as much on nailing pattern and starter course as on the product. Four nails in the wrong place behaves like two.
- Granule loss accelerates near the end of life, and the granules are the sun protection. Once they go, the asphalt underneath ages quickly.
- Algae streaking is common in humid regions such as the Lower Mainland, the Fraser Valley and parts of Atlantic Canada. Copper-containing granules are sold to resist it.
Service life in Canadian conditions typically lands somewhere between fifteen and thirty years, with ventilation quality and slope orientation moving the number more than the brand does.
Standing seam metal
Metal has two very different forms, and conflating them causes most of the disappointment. Exposed-fastener panels, the ribbed sheets common on farm buildings, are screwed through the face with rubber washers; the washers are the weak point and need revisiting as they age. Standing seam conceals its clips under the raised seams, lets the panel expand and contract freely, and has no penetration through the water plane at all. On a house, the second is what people mean when they talk about a fifty-year metal roof.
Where it earns its keep:
- Snow slides off rather than accumulating, which matters on a steep roof in a heavy-snow region. That is also a hazard: a slab of snow releasing over a front door or a driveway is dangerous, so snow guards above entrances and walkways are not optional.
- It tolerates ice far better than asphalt, since there are no laps for ponded water to work under.
- It is light, often around a quarter the weight of asphalt, which helps on an older structure.
- It can be installed to very low slopes that asphalt cannot handle.
The trade-offs are real. Installation is a sheet-metal trade, not a shingling trade, and a badly detailed valley or chimney flashing on metal leaks just as happily as anything else. Long panels in direct sun show oil canning, a slight waviness that is cosmetic but bothers some people. Walking on it to service a chimney or antenna requires knowing where to step. The noise complaint is mostly myth over a sheathed and insulated attic; over an open-framed porch it is not.
Cedar shakes and shingles
Western red cedar is a genuinely good roofing material in the right place, and a maintenance commitment everywhere. It must be able to dry from both sides, which is why it is laid over spaced sheathing or a ventilated mat rather than directly on solid plywood with felt. Starve it of airflow underneath and it rots from below while looking fine from the street.
It suits the Pacific coast, where it comes from, and it performs acceptably in drier interior climates. It is a harder sell in regions with long periods of snow cover sitting on the surface, and in dry, hot summers it needs a fire-retardant treatment. Some municipalities restrict or prohibit untreated wood roofing outright in interface zones, so check the local bylaw before falling in love with the look. Expect to clear debris and moss, keep overhanging branches back, and replace individual shakes over time.
Matching material to conditions
| Condition | Asphalt | Standing seam | Cedar |
|---|---|---|---|
| Heavy snow load | Fine on adequate slope | Strong, add snow guards | Workable, needs upkeep |
| Frequent freeze-thaw | Average | Strong | Average |
| High wind exposure | Good if laminated and nailed properly | Strong | Weaker |
| Low slope | Limited | Suitable to very low pitches | Not suitable |
| Wildfire interface | Acceptable | Strong | Restricted in many bylaws |
| Complex roof shape | Easiest | Costly detailing | Skilled labour needed |
A note on synthetic and composite products
Moulded polymer tiles and shakes have matured and now hold up well to hail and cycling, with a weight advantage over slate or concrete. They are worth a look if you want the appearance of slate or cedar without the structural and maintenance implications. Judge them on third-party impact and wind classifications and on how long the specific manufacturer has been shipping the specific product, not on the marketing name.
The part nobody shops for
Whatever goes on top, the assembly underneath decides how long it lasts: sound sheathing, eave protection membrane carried far enough up the slope, correctly lapped underlayment, proper flashing at every wall, chimney and valley, a drip edge, and an attic that is sealed and vented. A premium shingle over a soaked deck and a blocked soffit will underperform a mid-range one over a dry, breathing assembly, every time.