Pubdate: Mon, 13 Sep 2010
Source: USA Today (US)
Page: A4
Copyright: 2010 USA TODAY, a division of Gannett Co. Inc
Contact:  http://www.usatoday.com/printedition/news/index.htm
Details: http://www.mapinc.org/media/466
Author: Wendy Koch, USA TODAY

ON CUTTING EDGE OF BUILDING GREEN HOMES - WITH HEMP

Asheville, N.C., Pioneers Walls That Spare Trees

Hemp is turning a new leaf. The plant fiber used to make the sails 
that took Christopher Columbus' ships to the New World is now a 
building material.

In Asheville, N.C., a home built with thick hemp walls was completed 
this summer, and two more are in the works.

Dozens of hemp homes have been built in Europe, but they're new to 
the United States, says David Madera of Hemp Technologies, a company 
that supplied the mixture of ground-up hemp stalks, lime and water.

The industrial hemp is imported because it cannot be grown legally in 
this country - it comes from the same plant as marijuana.

Its new use reflects an increasing effort to make U.S. homes not only 
energy-efficient but also healthier. Madera and other proponents say 
hemp-filled walls are non-toxic, mildew-resistant, pest-free and 
flame-resistant.

There is a growing interest in less toxic building materials, says 
Peter Ashley, director of the Department of Housing and Urban 
Development's Office of Healthy Homes and Lead Hazard Control.

"The potential health benefits are significant," he says, citing a 
recent study of a Seattle public housing complex that saw residents' 
health improve after their homes got a green makeover.

The U.S. government has not taken a "systemic approach" to studying 
chemicals in homes and instead addresses problems such as asbestos, 
lead, arsenic and formaldehyde only after people get sick, says 
Rebecca Morley of the National Center for Healthy Housing, a research group.

Morley says green building so far has focused mostly on the 
environment, not the health of the people inside.

Ashley agrees that federal attention has been "sporadic," but says an 
interagency group began meeting last year to tackle the issue more broadly.

"We are taking the next step in green building," says Anthony 
Brenner, an artist who designed Asheville's first hemp home. "We're 
trying to develop a system that's more health-based."

Brenner says he has been searching for non-toxic materials because he 
wants to build a home for his 9-year-old daughter, Bailey, who has a 
disorder that makes her extremely sensitive to chemicals. "We have to 
keep her away from anything synthetic," he says, or she'll have seizures.

He says a hemp home can be affordable, even though importing hemp 
makes it more expensive than other building materials, because 
skilled labor is unnecessary and hemp is so strong that less lumber is needed.

The hemp mixture - four parts ground-up hemp to one part lime and one 
part water - is placed inside 2-by-4-foot wall forms. Once it sets, 
the forms are removed. Although it hardens to a concrete-like form, 
wood framing is used for structural support.

"This is like a living, breathing wall," Madera says. Hemp absorbs 
carbon dioxide and puts nitrogen into the soil, so it's good for the 
environment, he says.

Alex Wilson of Environmental Building News says hemp can be grown 
with minimal use of chemicals and water. He says it has a midlevel 
insulating value but is usually installed in a thick-enough wall 
system that makes it appropriate for all but the most severe climates.

The hemp mixture has not previously been used in U.S. homes, but in 
2008, it went into a community center on the Pine Ridge Reservation 
in Badlands, S.D., as well as a small chapel and pottery studio near 
Houston, says Mario Machnicki of American Lime Technology, a Chicago 
company that imports hemp from the United Kingdom.

Asheville's second hemp home will be finished in about six weeks, 
says builder Clarke Snell of the Nauhaus Institute, a non-profit 
group of designers, developers and others interested in sustainable 
urban living.

Snell says the home, which has 16-inch-thick walls, is airtight and 
energy-efficient. He expects it to meet rigorous Passive House 
Institute standards, which call for homes to use up to 90% less 
energy than regular ones.

"On the coldest day in winter, the body heat of 10 people should heat 
the home," he says.

Snell says his group will own the 1,750-square-foot house, and its 
engineer will live there for a couple of years to monitor energy use.

He doesn't know how much it will cost because, as a prototype, it was 
built with donations and volunteer labor.

The owners of the first hemp home say it cost $133 a square foot to 
build, not including land and excavation. "That's pretty remarkable" 
for a custom-built home in Asheville, which is a pricey area, says 
Karon Korp, who moved into the house in July.

Korp says she and her husband, Russ Martin, wanted primarily an 
energy-efficient home. They hope their house sets an example for the nation.

Martin says they have spent less than $100 a month to cool the home, 
which has 3,000 square feet plus a garage. Korp says they might add a 
windmill, because the house sits atop a mountain.
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