But modular construction can't handle irregularly shaped homes. Modular is not used in custom building or for the Southern-type house that sprawls all over," says Ms. McGee.
At the RBS factory in Northeast, housing modules roll through 33 stations on metal wheels, pulled by a portable forklift. Nearly all the necessary construction is done in the factory -- including framing and the building of floors, walls, ceilings and roofs. Most of the plumbing, electrical and heating work is also done at the plant. Windows, kitchen cabinetry and appliances are put in, as are bathroom tubs, vanities and even mirrors. In addition, the modules are painted on the interior and some finishing work is done at the factory.
There are limits. Fearing its modules will be damaged in transport, RBS deliberately avoids installing the exterior siding on the units. Rather, it places the siding, still in its brown paper wrapping, inside the units, ready for installation at the building site.
RBS constructs the units as wide as allowed to move along the roadways (16 feet in Maryland and 14 feet in some other states, such as Virginia).
Once they've gone through "punch out," a careful check of details near the factory's exit, they're jacketed in white plastic, lifted onto flatbed trailers and moved to the building site where finishing work is done.
RBS builds 70 houses a month at its Northeast factory, which employs more than 100 people. Keith Sholos, the company's executive vice president, says the average modular home is sold to a homebuilder for $45,000. In the Baltimore region, the builder is likely to pay $20,000 for the land on which such a home will be situated. After pouring the foundation, adding the driveway, landscaping the lot and otherwise finishing the house, the builder can sell it for $90,000, he estimates.
Although "pre-fab" housing has a reputation for shoddy workmanship, the promoters of RBS contend that the manageable conditions of a factory produce a superior house. They argue that it's logical to use mass production methods for ** housing, just like cars.
"In the controlled conditions of a factory, people are not bumping into each other and there's a tremendous efficiency in material handling," Ms. McGee says.
Builders who buy from RBS say modular construction offers several advantages over conventional homebuilding techniques.
Vandalism and theft of building materials are becoming serious problems at building sites, but modular housing generally spares the builder such costs, says Manning Klepsig, owner of a small homebuilding firm in Aberdeen. It also spares the builder worry about weather conditions, saves financing costs by speeding the building process, and allows the builder to reduce his work force and manage his overall costs, thereby lowering his level of business risk, he says.
Although most builders and homebuyers have a long way to go before they understand the capabilities of modular building, many builders who become RBS customers typically get hooked on the method.
"I love modular -- it's the only way to build," says Roy Klein, head of Klein Development Corp., a mid-sized builder based in Dover, Del.
"Would you buy a car that was built in your driveway or would you rather have one built in a factory in a controlled environment with highly skilled workmen?"
Regional Building Systems, the nation's largest builder of modular homes, is weathering the homebuilding recession by stressing affordable housing.