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Friday, September 3, 2010

House Built From Hemp Is Full Of Green Surprises

by Lloyd Alter, Toronto

push house hemp materials photo exterior
All images from Push House

In much of the world, hemp is thought of as a useful building material; Warren recently showed us an interesting house from Australia and it is common in the UK. But in America, it is still the butt of hippie jokes; Matt Hickman of the Mother Nature Networks describes a new house in Asheville, North Carolina with references to Tommy Chong and describes the interior: "there's not a blacklight poster, hanging spider plant, or crumpled up Cheetos bag in sight." Discovery News says "Put aside old visions of burlap-like shirts that belong with hacky sacks." Even the owner tells CNN ""We heard that we could have a really great neighborhood party if it ever caught on fire."

It's a shame that everyone is focusing on that, because it is just one interesting product in a fascinating house that is full of surprises.

push house hemp materials photo installation
Forming the walls- the black is formwork, on both sides of the structural wood frame

Push Design is a "Design firm with a focus on non-toxic/chemical free + clean air; living and working environments," and Anthony Breener appears to have looked at, and questioned, every single material in the house, from the foundations up.

Better Than Zero Carbon

The exterior walls that are getting all the sniggers are made from Hemcrete, a mix of British hemp stems that is grown without agrichemicals, and processed without a lot of energy and no toxic products. It it is chopped and graded and mixed with a binder made from hydrated lime. It sequesters 110 kilograms of carbon dioxide per cubic meter of material. The supplier, American Lime Technology, explains that industrial hemp won't get you high:

Henry VIII passed a law requiring all farms over 60 acres to grow hemp to satify his naval requirements. However by the mid 20th century the growing of hemp was outlawed because of its narcotic content (cannabis). The narcotic content has been selectively bred out of the industrial crop and the first licences for industrial grade hemp farming were issued by the UK Government in 1993.

push house hemp materials photo interior
Interior of exposed hemcrete

The stuff isn't structural, so the house has a wood frame, but it is a great insulator and sound absorbent, and will give a complete seal. It's neat stuff; it is a shame that it has to be imported from the UK because American attitudes to hemp are so silly. That is why all the sniggering and bad jokes make me so cranky; it deserves better.

More at Push House and more on other neat green features of the house tomorrow.

push house hemp materials photo detail
Hemp wall detail

More Hemp
The Whole Hemp House
Potential First U.S. Hemp Farmer Gets Fingerprinted