Greener Roofing Options

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Slate can last almost indefinitely, depending on the type, thickness, fasteners, roof slope and installation, with only minor maintenance. With the right tools and a little know-how, installing or repairing a slate roof is fairly straightforward. Reclaimed slate also is available.

“By recycling a slate roof yourself, you can own a lifetime stone roof for less money than the cheapest of asphalt roofs,” Jenkins says. “If you’re not that industrious, you can buy new or used slates and install them yourself with the proper guidebook and tools.” Professional slate-shingle installation also is widely available.

Under the Earth

Living roofs, covered with a dense mat of growing plants, are sprouting up on the tops of commercial and residential buildings in the United States as a way to reduce heating and cooling costs, and to improve local air quality. Urban heat-island effects (the tendency for large asphalt and concrete areas — such as in cities — to build up more heat than the surrounding countryside) also are reduced, as is storm-water runoff. Living roofs can detain more than 50 percent of rainwater from a typical storm, which reduces the loads placed on storm sewers in urban areas, according to Green Building Products.

Also referred to as a “green roof,” a living rooftop usually consists of a waterproof membrane, such as a modified asphalt or synthetic rubber (EPDM), over the roof sheathing. Next, a root barrier and drainage media are placed. On top of the drainage media, 2 to 6 inches of a planting mixture (lightweight aggregate, sand, organics, clay and silt) are laid. This soil structure supports drought-tolerant plants such as succulents, herbs, forbes, grasses and some low groundcovers.

Due to their weight and need for solid structural engineering, living roofs are better suited to new construction, rather than retrofits, although a structural engineer can help you determine the feasibility of your existing building structure for supporting a living roof. Water will add another 10 to 25 pounds per square foot when the living roof is saturated, so this roofing method shouldn’t be taken lightly. Weight requirements (including snow, where applicable) need careful consideration when a suitable roofing structure is designed for holding up all that earth.

Living roofs are now available from a handful of suppliers for either commercial or residential application. The Green Products Directory lists U.S.-based companies that specialize in this area.

One of the problems with living roofs is what to do if they ever spring a leak. Tracing the leak back to its origin can be a time-consuming exercise in frustration, and solving the problem may require some professional consultation and careful excavation.

Grass roots roofs

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