Cedar Shake & Slate

Cedar shake is still on many older Calgary roofs, and a lot of them are now at the point of a decision. Shakes dry out, split and cup in Calgary's dry air and strong sun, and moss or debris holds moisture on shaded slopes. A shake roof with some split pieces can be repaired; one where shakes crumble or the roof has open gaps usually needs replacing.

Replacing cedar with cedar is still done, but many owners move to a synthetic shake or slate made from rubber or polymer, or to a Class 4 impact-rated product. Those are lighter than real slate, carry a fire rating, and handle hail better than natural wood. Ask for the product's impact rating and how your insurer treats it.

Real slate and clay or concrete tile are heavy. The City of Calgary lists changing from shingles to clay roofing as work that needs a building permit, because the structure may not have been designed for the weight, and the same logic applies to any heavier material. The City's cost comparison puts slate at roughly 355 percent more than standard asphalt and clay at about 370 percent more.

Specialty roofs need specialist installers. Ask how many roofs of that exact material the crew has done, where you can see one, and how they flash valleys and walls on that product. Older homes built before 1990 can have asbestos in some roofing materials, and Alberta requires removal by trained workers.