The Amish have long been famous for barn raisings. Now, they're becoming known for building houses for the non-Amish, often using ancient construction techniques.

About 600 Amish contractors or subcontractors work in at least a dozen states, a rapid increase over the past decade, says Donald B. Kraybill, who has written more than a dozen books on the conservative Christian sect. Not only do some of them specialize in the timber-frame construction method that doesn't use nails, they often can erect a house faster and for less money than traditional contractors, customers say.

Yet working with an Amish builder brings special challenges. Imagine trying to keep in touch with a contractor who doesn't own a phone -- most are forbidden to have one at home. They also aren't allowed to drive, so they need a driver or other means to get to the job site. Few use computers, have insurance or will sign a detailed construction contract.

But some customers are willing to put up with these constraints for what they say is a better-built house. Kevin Heitland was so impressed by the workmanship of a friend's timber-frame house put up by Amish builder Danny Schwartz that he hired Mr. Schwartz for his new lake house south of Branson, Mo. The builder framed the 2,200-square-foot house using wooden pegs in less than a month, for a total cost of $129,000, including the exterior walls, insulation and three porches. (Other workers finished the interior.)

Mr. Heitland, a convenience-store owner in Nixa, Mo., says the work Mr. Schwartz did would have cost at least a third more and taken twice as long if he had used regular contractors. Now he plans to commission the same Amish builder for a spec house he plans to sell. "Their workmanship is second to none," Mr. Heitland says.

Customers such as Mr. Heitland are turned off by the anonymous and sometimes sloppy work of mass home builders. The Amish are known for careful woodworking, whether using the timber-frame technique, in which thick beams are assembled with wooden pegs and mortise-and-tenon joints, or the conventional "stick frame" approach using machine-milled lumber and nails. And in an industry known for unreliability and corner-cutting, the Amish -- a community known for its work ethic -- can be refreshing, customers say.

Seth Teter/ Ohio Farm Bureau Workers from Amish Timber Framers construct a house in Doylestown, Ohio, using the ancient timber-frame technique, which doesn't require nails.

Of course, there are plenty of non-Amish builders who take pride in their craftsmanship. Some use similar old-fashioned techniques, including timber frame. "There are good and bad contractors. It is more based on what someone is willing to pay than on whether the contractor is Amish or not," says Stephen Risser, head of the Department of Building Regulations in Richland County, Ohio. He estimates that work by Amish contractors and subcontractors makes up 20% of his department's inspections.

Amish builders trim costs by using family members as workers and keeping their overhead low. Many don't buy insurance, since their communities often have insurance pools to help pay hospital and other medical bills if a member gets sick or injured. (People who use Amish builders may need to buy their own liability policies.) Unlike many general contractors who use subcontractors, Amish builders tend to do all the construction themselves. That cuts out middlemen and allows them to immediately correct any problems on a job.

Matt Breyer, owner of Breyer Construction in Reading, Pa., says he regularly competes against Amish builders and "we usually get slaughtered" in pricing. He says a chief reason is his need to pay for unemployment benefits, worker's compensation and insurance. He lost a job last year to install a custom deck after he bid $50,000 and an Amish contractor bid half that, he says.

And while Amish contractors are hampered by the sect's restrictions, they find ways to work around the rules: Many can't own power tools -- but they can rent or borrow them. They aren't allowed to drive -- but they can use a car with a hired driver. Use of phones is banned at home -- but many are permitted to use cellphones for business or if someone else owns the phone, like the non-Amish driver.

"There's no question it is harder to get in touch with me," says Mr. Schwartz, the Amish builder who erected Mr. Heitland's lake house. Though Mr. Schwartz works out of El Dorado Springs, Mo., he has built houses as far away as Colorado and Montana. He says he has a driver but has also used taxis and gets rides from clients. Though computers are taboo, he hires non-Amish to do three-dimensional pictures of his hand drawings. In his shop, his tools are driven by horsepower using a contraption that resembles a merry-go-round, allowing up to four horses to turn steel shafts that are geared to saws and planers. But in the field he uses a non-Amish person's power tools.

Some Amish use non-Amish as conduits for their construction businesses. Cindy Shepherd, a real-estate agent at Mike Thomas Associates/ F.C.Tucker in Fort Wayne, Ind., agreed to develop a Web site and handle open houses and referrals for an Amish-owned builder of both spec and custom homes.

Deanna Vickery turned to Amish Timber Framers in Doylestown, Ohio, when she bought her grandparents' farm in nearby Dover, Ohio, and wanted to put an addition on the 100-year-old barn. Although the Amish generally aren't allowed to watch TV, if they happen to be in a room where the TV is on, they don't have to leave. As a result, she would be asked to show up at lunchtime to turn on football games for the workers. Mrs. Vickery says she quickly became friends with the crew, inviting them and their families to her annual pig roast.

About 20 years ago, the Amish started to diversify out of farming when it became clear that subdividing a farm among sons wasn't sustainable as their population grew and land costs made buying new property prohibitive. The Amish population has about doubled since then to an estimated 231,000 nationwide, says Mr. Kraybill, the author, who also is a senior fellow at Elizabethtown College in Elizabethtown, Pa. Many became entrepreneurs, carpenters, factory hands and artisans. Now, more than 70% of Amish household heads pursue nonfarm lines of work, Mr. Kraybill says. Typical Amish thinking views work as an overwhelmingly positive and even formative element of life, says Erik Wesner, a scholar who studies the Amish and runs a blog about them.

D.J. Wagner Cindy Wagner's Amish-built house in Fort Wayne, Ind., was erected in 4½ months.

Cindy Wagner, a 41-year-old surgical technician in Fort Wayne, Ind., used Amish builder Lee Schmucker's Imperial Homes to erect her 2,500-square-foot house. It was finished in 4½ months and cost $410,000, including high-end tiles and a walk-in shower, she says. "They were there every day, regardless of weather, and they did exactly what they said they would do -- and more," Ms. Wagner says. While she got a comparably priced quote from a non-Amish builder she went with Mr. Schmucker because she liked his work on one of his spec houses. "The craftsmanship was beautiful," she says.

Paul Hackett, an attorney in Cincinnati, chose an Amish builder to help put an addition on his 208-year-old house because it was the only company he found that could match the home's exposed, hand-hewn beams. Though he had to rent a trailer to fetch the beams from the Amish builder's shop, he says the process was fairly simple. "There are lots of painful experiences when you build a house, but not this," he says.

But sometimes the communications issues can be too much. Jim Zik, a telecom product marketing manager in Mount Airy, Md., heard from others about the quality of Amish builders and their low pricing. Mr. Zik says he tried for nine months to find an Amish home builder, putting out messages on Internet sites, asking Amish barn builders and talking with friends. Finally, he gave up. "I have a lead on a Mennonite now," he says, speaking of a related Christian sect also known for construction work. "They are allowed to drive and have phones, so it should be easier."

Write to Nancy Keates at nancy.keates@wsj.com

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