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Q.I’m about to take on a wood-shingle roofing job on an unusual roof with a lot of sinuous curves. I’m planning on steaming and bending strapping to provide a nailing base for the shingles, then steaming and bending the shingles, too. But isn’t there an easier way?

A.Martin Obando responds: You can make slight bends in shingles by just soaking them. But for serious curves, you’ve got to steam them. Get a book on wooden boat building or visit a boatyard if you want to learn how to steam wood — the same techniques that work for big timbers work for shingles. I’ve seen people rig up a steaming apparatus from an old beer keg, a piece of waste pipe, and a propane heater — if you’re handy, it’s not too hard.

Ten or 15 minutes of steaming will soften up shingles. Once they’re soft and you’ve bent them into the shape you want, douse them with cold water and they’ll hold that form.

However, when you start to get creative like this with shingles, you’re departing from their original purpose as a water-shedding roof and emphasizing their visual effect instead. It’s prudent not to push it. I’ve done a lot of decorative roof shingling, and in my experience, the best way is to start by building a submarine (that’s my term for providing a reliable waterproof layer under the shingles). In the old days, I would use two layers of 15-pound roofing felt with a layer of cold roofing mastic sandwiched between. Once products like Grace’s Ice and Water Shield came out, I started using those instead (doubled up and lapped — I don’t trust a single layer in freezing climates).

With a reliable waterproof substrate in place, you’ve got a lot more leeway with how you trim and arrange your shingles. For instance, in places where you reduce your reveals and leave just a few inches exposed to the weather, there’s no need for all that extra shingle that’s buried under succeeding courses in a standard triple-coverage application. For sharp bends, I’ll often cut quite a few inches off the thin end of the shingle to make it easier to work with. This way I can avoid some of that steaming and soaking.

Cutting down your shingles that way can make this job a lot easier (in tight spots, almost everybody gives in and does it). It may compromise the water-shedding capabilities of the shingles somewhat, but that decision was already made by the designer who put all the whoop-te-doos into the roof plan (that’s why I recommended a waterproofing membrane).

Compromising function for style means relying more on the membrane as your final defense against the rain. But the shingles will still shed almost all the water, and they’ll protect the membrane from the sun, too.

Master roofer Martin Obando is director of applications specifications for the Cedar Shake and Shingle Bureau.