Tuesday, April 20, 2010

Hemp: the farming of the future

Industrial hemp has a low-THC (Tetrahydrocannabinol) content and produces the longest, strongest plant fibres in the world. It is used in many countries in the manufacture of plastics, fiberglass, fabrics, food and building materials.

"In the UK, a major car manufacturer, Lotus, is making whole cars out of hemp," Klara said. "Everything but the engine is hemp. Henry Ford would be grinning in his grave."

Klara currently teaches sustainability courses at TAFE and envisions hemp as the solution to many of the sustainability issues that are affecting Australia today. Not only is she trying to create a hemp industry in NSW and open the way to using hemp seed as a food product, but she is out to make housing materials affordable. After looking around for alternative products to replace our current dependence on timber, Klara spent years experimenting with hemp masonry as a building material, with very successful results. Two years ago, she was a finalist for the Northern Rivers Regional Development Board's innovation award for her hemp masonry.

"When I was first researching hemp, I found an article that said ancient hemp masonry from 750 AD was found in southern France," Klara said. "The use of hemp in building has been around for a very long time."

In 1999, after applying for a special license to grow hemp under the Drug Misuse and Trafficking Act, she began growing experimental trial crops in the Hunter Valley. She then conducted experiments with the hemp stems at the University of NSW, using both the whole and separated stems as building materials.

"I now work with the whole hemp stem," Klara said. "It's expensive to separate the inside fibre or 'hurd' from the stronger outside fibre or 'bast'."

One of her first building projects with hemp masonry was retro-fitting a wall on her own house at Corndale. The process involved building a wooden framework with spacings between, then laying wooden planks 60cm high on the inside and outside of the wall to shape the mix. This shape was then in-filled with a mixture of chopped-up hemp and a lime-based binder to create a concrete-like structure. Once the mix was dry, the planks were moved up and more mix was poured in, building the wall higher every day.

Hemp masonry is a more sustainable, organic material than concrete and 'breathes' much like a wooden structure. This means that allergy-causing moulds won't form on it, creating a healthy environment in which to live.

"Building with hemp masonry is an example of cradle to cradle technology," Klara said. "If you decide to change your house, you can break up the hemp masonry and re-combine it to build a new wall.


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