After David and Roger Cohen figured out how to build whole houses in on-site neighborhood factories, they toiled for five or six years registering patents for parts of the process. The hard work was over, or so they imagined. Little did they realize that there remained the task of selling in the concept to an industry that operates fundamentally as it did scores of years ago.

"What I didn't realize was that didn't carry the day," says David Cohen.

"You really just have to see it to believe it. It's not modular, it's not pieces and parts, it's stick-built except in a factory." –Gene Myers, president, New Town Builders Photo: By Phil Mumford For two years, the brothers, who are engineers by training, tried to peddle their patented processes to large production builders only to get, at best, a pat on the back before being ushered out the door.

They tried to explain that they had developed the home builder equivalent of the Holy Grail, a way to build houses faster and better on an assembly line in controlled factory conditions and conquer the transportation barriers that plague other factory-built home scenarios by putting the factories in the neighborhoods.

The kinder builder executives explained during those housing boom years that there was no time or need to try any new building techniques when the old ones were working just fine, thank you. "Not only was it not of interest, it was an annoyance," recalls Cohen, a principal in Cohen Brothers Homes. "They were busy people, busy making money."

Others didn't understand the magnitude of the Cohens' concept. After all, pieces of homes are already being made in plants, either as panels or modular sections with varying degrees of success. How was this different? "They were from Missouri," the Show-Me State, says Cohen.

Seeing is Believing

Gene Myers, president of the small Denver-based New Town Builders, understands why big builders were skeptical. "You really just have to see it to believe it," he says. "It's not modular, it's not pieces and parts, it's stick-built except in a factory."

It was Myers who took the leap and gave the brothers a chance. Under the banner research and development, he contracted with them to build 237 homes in Newbridge at Tollgate Crossing, an Aurora, Colo., subdivision. He agreed to pay the Cohens what it would have cost New Town to build each house in the traditional on-site manner.

"We are working like the primary contractor, doing the work of like 25 subcontractors," Cohen says. "It's the client's land, client's design, client's sales force."

It took about 18 months from that agreement to get things going, but by last fall the 30,000-square-foot pre-engineered steel factory was up and the first of six townhouses were lined up on the five-slot assembly line. By New Years, the townhomes were in place on a nearby street and two-story, single-family houses were lined up on the production floor.

"It's taken three times as long as we thought," says Cohen. "This is not for the faint of heart. We were trying to do something comprehensive that truly affects the entire process in an industry that is not accustomed to dealing with that much change. But the good news is we have done it. It was very hard work and took a long time, but we've done it."

Even now that you can see it, it's a bit hard to believe. Five houses at various stages of completion lined up in a row inside a 30,000-square-foot corrugated steel building is a slightly surreal sight. The last house in the row sits perched at the edge of a huge open door, ready to be tugged onto a transporter and into the open air for the first time in its existence.

"This is not for the faint of heart. We were trying to do something comprehensive Photo: By Phil Mumford The house is complete from the shingles on the roof to the ceramic tile and hardwood flooring, from the doorbell to the toilet seats, from the exterior lap siding to the stove and dishwasher. The only things missing are some decorative brick and some other external trim that will be added after the house spends a couple of hours creeping toward its new address. There, it will be slid onto a pre-poured basement wall foundation where its steel frame bottom will be welded to steel plates imbedded in the concrete foundation walls.

Even Myers is still amazed to watch a whole 35-ton-house move down the assembly line, a task that can be accomplished by as few as six men leaning on it and shoving. Moving the houses is easy thanks to a dozen to 18 wheel-less casters, which function like little hover crafts, literally levitating the house half an inch as compressed air shoots out the bottom. It's actually easier to rotate a house in place to paint each side rather than having to disassemble and reassemble the line of scaffolding.

The Cohen brothers are just beginning to scratch the surface of home building improvements that can be done more easily inside a factory on an assembly line than at a jobsite. There are the obvious advantages that builders have craved for years, such as the ability to keep everything protected from the weather and having the same workers doing the same tasks every day. The factory environment was one much appreciated during Denver's recent severe winter. The only weather-related delay was when one of the houses got temporarily stuck in the mud on the way to its lot after the spring thaw.

Already the factory has been able to better optimize materials usage by using computer-guided saws. The list of materials needed, as well as the price, could also be cut more by designing the homes to optimally use materials, buying in bulk, and using volume discounts because supplies can be delivered to one place and stored there rather than bought piecemeal by subcontractors. "We buy every nut and bolt in our houses," says Cohen.

The Aurora plant serves as a pilot for the concept. Plans for the next factory call for closer to 50,000 square feet rather than 30,000. A bigger factory building would give the Cohens a chance to apply more advanced construction techniques, such as completing bigger pieces of the house on the floor using jigs and then hoisting them in place. An example might be the roof section of a house that could be completed from the shingles on the top to the second story drywall ceiling, and then lifted on top of the walls in one piece.

But for now, construction inside the factory looks very much like construction outside. The Cohens don't even call the construction process itself revolutionary because they use a variety of tools and techniques that have been available for years, sometimes in applications other than production home building, but still pretty common. "This isn't rocket science," says Myers. "We are basically stick-building a house in a closed environment. There is no alchemy going on here. This is really common sense."