Cheat Sheet | Picking out, taking care of the roof over your head

Winter's finally given the rooftops their first dusting with snow. But if every falling flake made you wonder whether your roof would survive another season, it's time to consider these points, brought to you with help from the Department of Energy and roofing-material manufacturers.

Need to know: Which kind of roof you have - flat, sloped or peaked - and what kind of weight it will bear. This will determine the most appropriate roofing material. (Asphalt shingles aren't right for a flat roof, for example).

Slate of candidates: Slate is probably the longest-lasting roofing material, but it is typically the most expensive and is heavy. Fake slate roofs, made of an engineered material, are less expensive and lighter.

Asphalt shingles are the most common and economical roofing product. (Asphalt also is used in roll-roofing, built-up roofing, and modified bitumen membranes.)

Single-ply Thermoset membranes, made from rubber polymers, are often called "rubber roofing"; they can withstand the potentially damaging effects of sunlight and most chemicals found on roofs.

Shingle file: New manufacturing techniques mean asphalt shingles are longer-lasting, and some companies offer lifetime warranties. There are four types of shingles: strip, laminated, interlocking, and large individual shingles.

Laminated shingles consist of more than one layer of tabs to provide extra thickness. Interlocking shingles are used to provide greater wind resistance, making them most appropriate for the Shore. Built-up roofing is used on flat or low-sloped roofs in the city and consists of multiple layers of bitumen and ply sheets. Components of a system include the roof deck, a vapor retarder, insulation, the membrane, and a surfacing material - usually a coating of hot asphalt.

More material culture: Metal roofs, common long ago, are making a comeback - in steel, aluminum and copper, among other types. To reduce the corrosion rate, steel is galvanized with a zinc or zinc/aluminum coating. Metal is available as traditional seam-and-batten roofing, tiles, shingles, and shakes, and new metal roofs last two to three times longer than asphalt.

Wood shakes look different on every roof. But in addition to a distinctive appearance, they can help insulate your attic and allow your house to breathe, circulating air through small openings under the felt rows on which the wooden shingles are laid.

Traditional roofing tiles are made from clay. They are durable and low-maintenance, provide energy savings, and are environmentally friendly. Because the ultimate longevity of a tile roof also depends on the quality of the subroof, manufacturers are working to improve flashings and other aspects of the underlayment system.

Good advice: Wood shakes require regular maintenance and repair. Mold, rot and insects can be a problem. Old shakes cannot be recycled, and most are unrated by fire-safety codes. Some pressure-treated shakes are impregnated with fire retardant and meet national fire-safety standards. Others have retardants sprayed on, but the retardant needs to be renewed periodically.

What will it cost? That depends on the material selected and the labor costs for your area. Pillar to Post, a national home-inspection firm, suggests a range for sloped roofs of $1.50-$2.50 for asphalt shingles to $50 a square foot for slate. Flat roofs range from $1 a square foot for 90-pound roll-roofing asphalt to $10 a square foot for single-ply membranes.

An ounce of prevention: Improper installation or faulty materials can compromise a roof. Make sure your roofer provides written proof of material and workmanship warranties.

Have questions or ideas for Alan J. Heavens? E-mail him at or write him at The Inquirer, Box 8263, Philadelphia 19101.