When David Welch, owner/president of Ben Hill Roofing & Siding, in Douglasville, Ga., gives prospects a rough estimate for a slate roof job, they sometimes balk. “The first thing they say is: I didn't want to buy another house.”

In fact, Welch points out, slate roofs can run to six figures, depending on the size of the building. Some customers insist on nothing less, he says. “They don't want anything artificial.” Some, on the other hand, want the classy look of slate, but can't afford its price tag. That's when Welch suggests synthetic slate, which Ben Hill Roofing also installs.

Growing Awareness Synthetic slate has been around for at least two decades, but in the last five years, the material has grown in popularity as manufacturers have improved product quality and as upscale roofing materials — copper, steel, tile, and natural slate — have become more attractive to architects and homeowners. Fort Worth, Texas, roofer Paul Ramon says that five years ago, his Ramon Roofing did roughly 10% of its volume in synthetic slate. Today the product accounts for about a quarter of the company's revenue. Brian Stearns, co-author of The Slate Book, estimates that use of synthetic slate has more than doubled since 2000. “It's easy to use, and there's no maintenance,” he explains.

Other considerations include waste and weight. Depending on product quality — determined by where it's quarried — slate can suffer significant breakage during installation. Joe Jenkins, who operates the Slate Roof Central Web site offering information and specialty tools, blames much of that on low-quality imports.

In addition, natural slate puts a load of anywhere from 600 to 1,200 pounds per square on the roof structure. Synthetic slate — made from rubber, plastic, resins, or a combination of these materials — is estimated to weigh anywhere from 200 to 600 pounds per square, depending on product.

Ramon says that in addition to stressing the look, weight, and cost — roughly half the price of natural slate, mostly because it can be installed in half the time — he stresses impact resistance and the fact that synthetic slate is a fireproof product, both of which can earn homeowners insurance discounts.

Au Natural Meanwhile, synthetics have yet to put a dent in the steady growth of natural slate. Stearns cites a sixfold increase in shipments of product from the New York/Vermont slate-producing region between the late 1970s and 2000. Nantucket roofing contractor Jim Lydon is among those preferring natural slate, supplies of which are now easily located via the Internet.

“I understand the advantages of synthetic,” he says. “It's fast and light. But I don't like the way it looks. It's too flawless.” Lydon says natural slate roofs, with their discoloration and other “little imperfections,” age with the house, but continue to function for 100 years or more.