Elements of roof repair

When it comes to re-roofing your home, a little knowledge goes a long way

By Martin Zibauer

shingles

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According to Dave Gordon, a roofing contractor in Nunavut, roofs there are unique because “the wind would get in and basically peel off the roof. Or snow would blow through the vents.” That’s why most roofs in Nunavut are covered with metal and built without vents to keep the wind and snow from blowing in. In fact, most Arctic roofs are built much like an insulated wall.

In Saint John, N.B., “Almost 95 per cent of the roofs in the downtown core are flat,” says Bruce Dowd, president of Dowd Roofing. That’s because in 1877 The Great Fire of Saint John destroyed much of the city, and not long afterward the city adopted a building code that required flat roofs so firefighters would have easy access to the rooftops.

Obviously, roofs are built differently across the country for good reason-although some fundamentals apply no matter where you live. If you’re considering a new roof for your house, your choice of roofing materials will probably be determined by two main variables: climate and budget. That said, aesthetics may also sway your decision-what looks right on your house and how much of your roof is visible from the ground.

Asphalt shingles

Chances are, you’re reading this under a shingled roof. Most Canadian residential roofs are protected by asphalt shingles, including the familiar three-tab shingle and newer, thicker laminated shingles. A relatively inexpensive option, they’re priced at about $45 to $60 per square (a square is a standard roofing measurement, equal to 100 square feet). While they don’t last as long as some other roofing options-usually between 15 and 30 years-the lower cost of asphalt often makes it the best value.

Traditional asphalt shingles come in a wide variety of styles and colours, including versions with scalloped or irregular edges; three tabs or none; and colour shading to suggest dimension. For high-wind areas, there are shingles that interlock, and for damp areas, there are shingles resistant to moss, mould or algae growth.

Shingles, like health care and vowel pronunciation, distinguish Canadians from our American neighbours. In Canada, asphalt shingles made with organic felt (a mat of wood and other cellulose fibres) dominate the market. In the U.S., almost all shingles use a fibreglass felt. With both types, the felt is impregnated with asphalt (a bituminous hydrocarbon usually obtained as a byproduct of oil refining) and embedded with coloured mineral granules that prevent ultraviolet light damage.

Organic shingles, often made of defibrated wood fibres and asphalt, usually last between 15 and 30 years, and typically the heavier they are, the longer they last. Most organic shingles are more tear-resistant than fibreglass and remain more flexible in cold weather, key reasons they’re a Canadian favourite. According to Dowd, heavier organic shingles rated for 25 to 30 years are the best value for Canadian homeowners.

Fibreglass shingles are lighter and hold up better in heat. But they usually require an asphalt felt underlay, and some become brittle in cold weather. Newer fibreglass shingles that address these problems aren’t yet very popular here, but that may change within about five years, predicts Norman Shore, sales manager at Toronto-based Dominion Roofing. He feels demand will be driven partly by insurance companies that like their fire resistance.

Laminated shingles, also called architectural shingles, are made of multiple layers of felt (organic, fibreglass or other mixtures) sandwiched for a more three-dimensional appearance. They give more visual texture to a roof, and come in various styles suggesting the look of slate, cedar shakes or other materials. They’re more expensive than three-tab shingles, at about $100 a square. And in part because they’re thicker than three-tab shingles, they’ll probably last longer. Some single-layer shingles are shaded with colour to create the two-layer look of laminated shingles.


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