Greener Roofing Options

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Thatch roofs, made with the dry, coarse stems of reeds or grain crops, have been commonplace wherever these materials exist for thousands of years.

A common misconception is that thatch absorbs large amounts of water. In fact, in a thatch roofing system water is transferred down the roof from stem to stem until it drops. The steep pitch usually (at a ratio of 12:12) associated with thatch roofs allows for water to be shed at a very fast rate, according to the Building Conservation Directory (www.building conservation.com), a Web site dedicated to the conservation of historic buildings.

Besides being water-resistant, thatch roofs are wind-resistant. And, because of the thousands of air pockets between and within the plant material, thatch also is a good insulator, providing a R-value of about 40.

Fire can be a concern, however, and thatcher Colin McGhee of Staunton, Va., says that to comply with fire codes on public buildings, his company treats its thatch with an odorless, nontoxic fire retardant. “But thatch, as it’s used in roofing applications, is inherently very fire resistant,” McGhee says.

Thatch reed roofs are long-lasting, with life spans estimated between 50 and 100 years, if constructed and maintained properly, McGhee says. “Every 12 years or so, thatch roofs need a brushing and dressing off, and the ornamental ridge replaced. I’ve worked on [thatch] roofs in England that are more than 100 years old and still going strong.”

But at a considerable price per installed square foot, most of us don’t have deep enough pockets to roof our houses with thatch. If you’re entranced with thatch, consider tackling a smaller project such as a garden shed or gazebo. For do-it-yourselfers, McGhee sells inexpensive, “shaggy” thatch mats at less than $5 per square foot.

Recycled Roofs

The rise in popularity of green building has produced a large variety of recycled roofing materials, ranging from rubber shingles to imitation slate tile made from recycled plastic and waste-wood composite. Known as polymer-composite or synthetic roofing, these products have the advantage of being lighter than clay tile or slate. Their inherent flexibility makes them resistant to hail damage, high winds and even occasional foot traffic. Made primarily of synthetic materials, they also resist organisms that promote decay. Most polymer roofing materials carry 40- or 50-year warranties, but also carry a high initial cost, often about $3 per square foot.

Panelshake roofing panels, molded from a mixture of old milk jugs and waste-wood fibers, mimic the look of natural slate and tile roofs. Another composite roofing product, Enviroshake, combines reclaimed materials such as recycled plastic, agricultural flax- and hemp-fiber waste and a little bit of post-consumer recycled tire rubber. Touted as an alternative to traditional cedar shakes, Enviroshakes incorporate UV protection with excellent mold-, mildew- and insect-resistant properties. Once installed, they are almost maintenance-free. By using 60-percent to 70-percent recycled tire rubber, Euroslate moves rubber from the road to your roof. And as an interlocking roofing system, Euroslates offer a similar look to slate.

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