See other Science/Tech Articles
Title: Hemp homes are cutting edge of green building
Source:
USA Today
URL Source: http://content.usatoday.com/communi ... /hemp-houses-built-asheville/1
Published: Sep 13, 2010
Author: John C. Fletcher
Post Date: 2010-09-13 20:32:27 by Ferret
Keywords: None
Views: 711
Comments: 56
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 in the past two decades, but they're new to the United States, says David Madera, co-founder 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. The home's bathroom has efficient lighting and water-conserving plumbing fixturesCAPTIONBy Peak Definition"There is a growing interest in less toxic building materials, says Peter Ashley, director of the U.S. 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, executive director of the National Center for Healthy Housing, a private research group. She 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. He says HUD is funding more research on the health and environmental benefits of eco-friendly homes. Some green-rating programs, such as the one run by the private U.S. Green Building Council, give points for indoor air quality. "We are taking the next step in green building," says Anthony Brenner, a home designer with Push Design who created Asheville's first hemp home. "We're trying to develop a system that's more health-based." Brenner says he's been searching for non-toxic materials because he wants to build a home for his 9-year-old daughter, Bailey, who has a rare genetic disorder that makes her extremely sensitive to chemicals. "We have to keep her away from anything synthetic," he says, or she'll have seizures. •Follow Green House on Twitter 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 — typically four parts ground-up hemp to one part lime and one part water — is placed inside 2-foot-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, executive editor of Environmental Building News, says hemp can be grown with minimal use of chemicals and water. He says it has a midlevel insulating value (R-2 per inch) but is usually installed in a thick enough wall system to make it appropriate for all but the most severe climates. The mixture, "Tradical Hemcrete," 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, managing director 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, engineers, 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. "We're basically building a European home." 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 home in Asheville, which is a pricey area, says Karon Korp, a writer who moved into the house in July. Korp says she and her husband, Russ Martin wanted primarily an energy-efficient home. They're not particularly sensitive to chemicals, but they were drawn to Brenner because of his modern aesthetic and green building enthusiasm. She says they're thrilled their house is made of a renewable, toxic-free material and hope it sets an example for the nation. "Hemp could replace tobacco if it were legalized," says Martin, Asheville's GOP mayor from 1993 to 1997. He says some area tobacco farms have gone bust. Martin says they have spent less than $100 a month so far to cool the home, which has 3,000 square feet plus a garage. It has 12" thick walls, Energy Star appliances, dual-flush toilets, high-performance windows and LED lights. Korp says they might add a windmill, because the house sits atop a mountain. They say they have fantastic views. "We seen the sun rise," he says. She adds, "and the sun set."
In Asheville, N.C., Anthony Brenner holds a handful of industrial hemp shiv, left, and a block of the finished hardened product after the shiv is mixed with hydraulic lime. He designed a home with thick hemp walls that was completed this summer and is currently working on another one that will use hemp on interior walls. 
The hemp home was built for $133 per square foot, not including land and excavation costs, at the top of a mountain. 
The kitchen has clerestory windows for natural daylighting and Energy Star appliances. 
The home's bathroom has efficiency lighting and water-conserving plumbing fixtures 
A 2,ooo square foot with thick hemp walls was completed this summer in Ashville, N.C.
Post Comment Private Reply Ignore Thread
Top • Page Up • Full Thread • Page Down • Bottom/Latest
Begin Trace Mode for Comment # 48.
#27. To: Ferret (#0)
Yeah, after thousands die from asbestos homes, no wonder.
Not just that but a lot of the insulating materials they've been using, the plastic vapor barrier, and acrylic varnishes, and such, give off toxic vapors that make people sick. Some people are very sensitive to them and others not, but think of it as a "Canary in a Coal Mine". Just because some people have a higher tolerance does not mean there are no long term effects.
this is a cool thread. Original_Intent is correct in his statement that there are other low-tech type methods of building homes that are less expensive and superior compared to what home-builders typically do. The spiraling up of land prices has been perplexing. it has been due to financial engineering as far as I can tell because we've been losing jobs as a ratio to our adult population since 2000. and during this time we've seen land prices spiral, not just increase, but multiply upwards in many places. In the construction industry over the last 25 years we've witnessed material prices sky-rocket. Just between 1989 & 1993 lumber prices tripled. every type of material, portland cement, steel, everything has spiraled upwards. Soil is a very excellent building material for some things. There are some places in the US where you could cut soil blocks out of the ground and it would be as strong as a concrete block. In some places the soil can actually test out at 2,000 psi in a compression test. that's without compaction or any fibers added, just plain natural in situ soil. These are excellent ideas and it is so amazing how the home-building industry with all its money can't find them. True that walls made of soil are too thick because they're built thicker for strength. but there are still a lot of good ideas to facilitate low-cost home-building. That guy in New Mexico simply compacts by hand soil into rubber tires. and that is a very strong low-cost simple structure. In rural areas you don't need to worry about the thickness of the walls because you have land. The people who run home-building firms care about one thing. that is money, profit maximization is very important, avoiding the risk that money might be lost is extremely important. Their focus on money is so strong that they cannot see anything else. Also, they are finance and marketing oriented. the technical people who can work with ideas like this are pushed aside inside such organizations.
And there are other technologies as well. Earth bermed homes with concrete slab walls are also less expensive and very energy efficient as the internal temperature is moderated both winter and summer by the temperature of the ground. The two big problems are financing and building codes. Antiquated codes are used to determine whether a structure is sound and they are all written for brick and timber built homes. Some codes allow for concrete block construction, but those are all more expensive than other designs and technologies which are less expensive. As well is the fixation on "bigger is better". No, better is better. There are also a growing number of designs for small homes that live large. Efficient use of space, careful attention to design and layout can allow a 1200 sq ft. home live like a 2500 sq. ft. home. There are even designs for micro houses for 1 or 2 people that are as small as 100 sq. ft., but yet are very livable. I have seen well laid out designs for a slightly over 600 sq. foot 3 bedroom house. There are a lot of possibilities and technologies once you start thinking "outside the box".
#49. To: Original_Intent (#48)
We're meeting with a gentleman on Sunday to get ideas and estimates on converting a barn built in the 1800's (on land we're due to inherit) into a living residence. The frame is in perfect condition (12x12's!). He has a lot of ideas he's already floated past us, including "non-traditional" type exceptional R value walls and geothermal dug in at the onset. His designs turn barns into essentially super energy efficient buildings, the size of small Chalets. :)
Top • Page Up • Full Thread • Page Down • Bottom/Latest"There is a growing interest in less toxic building materials,..."
#28. To: RickyJ (#27)
#45. To: Original_Intent, Ferret (#28)
#48. To: Red Jones (#45)
Replies to Comment # 48.
End Trace Mode for Comment # 48.