When he talks about building a house out of dirt in a historic Roanoke neighborhood, architect Gregg Lewis begins to look just slightly maniacal.

Ordinarily reserved and neat, his hands begin to help him speak. The possibilities and the anticipation percolate in him, and he starts to look something like a mad scientist staring into a test tube waiting for a world-shaking chemical reaction.

The house made of dirt - it's actually an established environmentally sensitive building technique called "rammed earth" - is one part of a larger experiment Lewis, 41, has been presiding over since April 2004.

Lewis and his firm, SmithLewis Architecture, orchestrated the C2C home design competition as a means of promoting green building concepts championed by internationally known architect William McDonough in a book he co-authored, "Cradle to Cradle: Remaking the Way We Make Things." The idea is to move toward building materials and methods that will do less harm to the environment, such as solar energy and synthetic and recycled materials.

The contest hits its next phase at 10 a.m. today at a ceremonial groundbreaking in a vacant lot at 314 Hackley Ave. in Gainsboro to launch the actual construction of eight of the houses submitted for the competition.

But here's the mad part: No one has ever actually done this before.

The C2C principles have been used in furniture and in elements of houses, but no one has ever built a full-on C2C house, let alone eight.

"It's a huge experiment," Lewis said. "It's not enough just to have the idea. ... You have to have the practical part of, can you build them?"

More than that, he said, "We need to show this works for the person making $35,000 as well as it does for the person making $350,000."

The plan is to build the houses at moderate costs and sell them at reasonable prices, but high enough to elevate the value of neighboring properties.

The unknowns in the process seem to invigorate Lewis.

City building inspectors may never have seen this kind of construction before. The builders involved have likely never used such materials and techniques as "rammed earth" or passive solar heating.

The houses could be financial flops. Lewis expects the houses will sell for $90,000 to $150,000, but the building costs could range from $90,000 to $200,000.

Everyone involved needs to be willing to fail, Lewis said. "To me the best thing about a failure is what you can learn from it."

Plenty of others seem willing to take the risk.

Lewis has a list of eight potential home sites, including one on Hackley Avenue that is owned by the Roanoke Redevelopment and Housing Authority. Old Southwest is considering offering a lot the neighborhood association owns on Day Avenue.

Fralin & Waldron, which usually handles major developments, and E.J. Miller Construction, a custom home builder, are planning to partner on the rammed earth house at the Hackley site.

Construction could begin within weeks on as many as four or five other houses, Lewis said. Only two of the eight designs were declared winners in the contest, which was juried by a panel of internationally known architects.

Others interested in building houses are Blue Ridge Housing Development Corp., Community Housing Partners, Total Action Against Poverty, and Habitat for Humanity.

Construction sponsors include BASF, the Carilion Foundation, the city of Roanoke, James Hardie, the Home Depot Foundation, Roanoke Regional Homebuilders Association, Wachovia Bank and the Landmark Foundation, which is affiliated with The Roanoke Times.

"All of these folks know we need to make some changes in the way we're doing things," Lewis said. "We need to make this as enjoyable as possible for everyone so they will continue to learn with us, grow with us, struggle with us."

The whole affair amounts to a huge leap of faith, including the notion that anyone will want to buy a C2C house.

"To me, it seems like, why aren't people lining up to get these houses?" said River Laker, 38, who works in the Roanoke City Neighborhood Services department.

Laker, an Englishman who has lived in the United States for 15 years, took an interest in a C2C house as soon as he heard about the contest. He's already pre-qualified for a loan and is itching to buy the Ekaterina Kohlwes-designed house planned for the Hackley Avenue site.

"It's contemporary, but it has a simpleness to it," Laker said. "I'm not sure it's going to be within my budget."

He's attracted to the environmental sensibility of the houses, and to how they might revitalize Roanoke's older neighborhoods.

Laker is single and currently rents an apartment in Old Southwest.

"This might help me find a wife," he said with a chuckle, "having one of the coolest houses in Roanoke."

On the Net:

www.c2c-home.org