Cedar shake roof replacement, Calgary

Why cedar roofs wear out in Alberta

Cedar dries out and weathers in Alberta's dry air, strong sun and chinook winds, then takes on water again with every snowmelt. That cycle cups, curls and splits shakes, and a winter chinook adds freeze-thaw on top. Hail breaks shakes that are already brittle. Keeping a cedar roof going means cleaning, re-treating and replacing pieces. Aluminum absorbs nothing, cannot rot and has nothing for freeze-thaw to work on.

A cedar roof always comes off before an Interlock® roof goes on. That tear-off is in the written price from the start.

Keep the look: Shake and Cedar Shingle profiles

Interlock's Shake profile has deep, hand-split shadow lines; the Cedar Shingle profile has the flatter look of a sawn cedar roof. Both are aluminum, lock on all four sides with the fasteners concealed, and weigh roughly 2 to 3.5 kg per square metre depending on profile.

At least 54 of the completed roofs in our Alberta job book are Shake or Cedar Shingle profiles.

Hail and cedar

Hail is a fact of roofing in much of Alberta, and weathered cedar doesn't take it well. Interlock® aluminum panels carry a UL 2218 Class 4 impact rating, per the Intertek / Delta Building Products listing. No roof is hail-proof. If you are asking about insurance, ask your insurer what an impact-rated roof means for your policy.

Fire, cedar and the wildland interface

FireSmart's roof fact sheet is blunt: avoid wood shakes or shingles. It recommends Class A roofing, and lists metal among the Class A materials. Embers from a wildfire can travel long distances and ignite a combustible roof. The 2016 Fort McMurray wildfire burned about 2,400 homes and buildings, and the Insurance Bureau of Canada put its insured cost at $3.58 billion, the costliest insured disaster in Canadian history at the time.

Class A Fire Rated Available, as a complete assembly: two layers of GAF VersaShield® over 12 mm (15/32-inch) plywood, per ASTM E108 (CAN/ULC-S107 is the Canadian counterpart). The rating belongs to the assembly, not to the panel alone, and aluminum itself does not ignite. No roof is fireproof; gutters, vents and the roof edge need attention too. That matters most for an acreage, a foothills property or a mountain home in the Bow Valley.

The Town of Banff has run a Combustible Roof Replacement Incentive Program for owners replacing wood roofs. Wherever you live, check with your municipality for what is offered and required at your address.