Most people don’t associate the glossy photos of beautiful, sustainable showpieces in author Sherri Koones’ books with modular construction.

That’s because factory-built, panelized, structural insulated panels (SIPs), timber-frame, and even metal-frame dwellings, “are virtually indistinguishable from site-built homes,” she told attendees at the recent NAHB Green Building Conference in Raleigh, N.C.

The author of two books on modular construction, including the new Prefabulous + Sustainable, said that homes built off site are “intrinsically green” for many reasons:
--they generate only a small amount of construction waste
--there is little disturbance to the building site
--they are energy efficient and boast a tight building envelope
--they are eligible for points in  national green building programs
--subs don’t have to travel to far-away jobsites, saving gas and other transportation costs.

“The plumber and carpenter, instead of traveling across several counties to one or two homes a day, can put in the materials for four houses in one day in one factory,” she explained.

In addition, prefabrication is one of the fastest, least expensive ways to build a green home. A study comparing the construction of identical houses, one site-built with conventional framing, the other panelized, found that the panelized project saved 253 hours of labor and $4,560 in labor costs.

Builders are reluctant to give up their site-built ways, Koones said, but “once they see how quickly and easily prefab houses go up, they’re sold.”  “No one I have talked to for any of my books has ever gone back to building on site.”

Co-presenter John Connell, director of design at Middlebury, Vt., prefab builder Connor Homes, offered these tips for green builders and architects considering  modular:
--Choose your prefab company carefully and stay close to your market to keep delivery charges down. There will most likely only be a few in your area, so research them in depth. “There’s not going to be endless vendors to choose from,” he said. (To find a vendor, go to the NAHB’s Building Systems Councils Web site.)
--Attend a training program; many prefabricators offer free educational sessions. “If you pay attention to about a half-dozen rules, anyone who knows how to build traditionally can build this way,” Connell said.
--Get to know the production staff at the panelized factory, not just the salespeople. Take a tour of the plant and visit the assembly line on the day of your project’s creation
--Go to a set to observe the project from start to finish. “See how problems are fixed.”

In closing, Connell urged attendees to consider eco-friendly alternatives to site-built dwellings.

“Factory-built homes now can be incredibly beautiful and are the standard now for sustainable homes,” he said. “It’s not that they’re just as good as site built, they’re way better.”

Jennifer Goodman is Senior Editor Online for EcoHome.