Installation is another tricky issue. Many of these products require fastidious assembly to achieve the desired look and performance. The conundrum architects face is whether to use a commercial installer familiar with the material or a residential contractor familiar with the house type. “Most of the time we end up with residential builders who are smart, creative, and courageous,” Johnston says. “We bring them in early so they can be a part of the design team.”

Bateman says installation is especially important for Parklex, which weighs about 90 pounds per sheet: “It can be hard to work with. It needs pre-drilling, and it has to be put on a furring system.” Architect Geoffrey Warner, principal of Alchemy Architects in St. Paul, Minn., used Parklex on a Wisconsin project in 2002 and loved the way it “made the house come alive and created a hybrid Modernist/traditional house.” At the time, he says, the panel was first-generation in this country, and there was some rippling of the edges. The manufacturer has since corrected the problem in a second-generation product, he adds. Warner's design tip for Parklex: Have your contractor cut the product long and then rout the edges. It adds to the cost, he says, but gives it a nice finished look.

As with commonplace products, it helps to know as much about the materials as possible. For instance, U.S. Steel, which manufactures Cor-Ten, doesn't recommend the product for architectural applications, because of corrosion risks. Ken Geremia warns that copper corrodes steel, so the two should never touch; use stainless steel instead. Carrie Meinberg Burke notes that the two materials are also very different to handle during installation (copper is much softer than steel). Because Burke is also interested in eco-design, she investigated the environmental repercussions of using copper. She and her husband recycled all the leftover scraps and designed a wetlands area planted with cattail to remediate and absorb the copper contaminants that run off before the metal oxidizes and sets.

Even when the advantages are clear, you may have to sell your client on the benefits of your unusual product. And this could be the toughest part. “It certainly requires a client to think differently,” Jeff Langham says. But if you present a strong, well-researched case on the beauty, low maintenance, and longevity of the material, you can convince your clients to side with your siding.