17 Aug 2007 @ 22:17, by Raymond Powers
Building straw houses; From flax to hemp, researchers tout merits of bio-construction
By Jennifer Pritchett
The Whig-Standard - Kingston, ON, Canada
August 17, 2007
Local News - Fuelled by a growing demand for environmentally friendly buildings, hemp, wheat, flax and other grains are now being touted as emerging raw materials in the construction industry.
The merits of these so-called "biofibres" and their applications in Canada, the United Kingdom and other parts of the world was the basis of an international symposium that wrapped up in Kingston yesterday.
Shelagh McDonald, executive director of the Eastern Lake Ontario Regional Innovation Network, which organized the event, said the symposium brought together the researchers and industry leaders who are using biofibres to foster new developments.
"I know there are going to be some collaborations that will spark as a result of bringing people together," she told the Whig-Standard.
The Eastern Lake Ontario Innovation Network, partially funded by the province, promotes the bioproduct, biomedical and bioenergy industries.
The symposium attracted about 100 participants from Canada, the United States, Africa and the United Kingdom.
Participants in the symposium toured a hemp experimental farm near Belleville on Wednesday.
Over the two-day conference, a handful of guest speakers tackled topics such as using biofibres in the construction industry and combusting the material to turn it into green energy.
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Speaker Colin MacDougall, a professor of civil engineering at Queen's University, leads a group researching straw-bale homes. He spoke yesterday about the work the group is doing inside a Queen's laboratory to learn more about the strength of walls made from straw bales.
So far, he said, the results show that straw-bale walls are durable and strong if constructed properly. "The performance seems to be pretty good," he said.
The group's tests look into what type of fibre bale, including flax, hemp or wheat, works best. They're also looking at what types of plaster, including clay or cement, applied over top of the bale, are more durable. They're even looking at the placement of the bales - flat or on edge - to find out which design is more stable.
The Natural Sciences and Engineering Research Council of Canada and the Canada Mortgage and Housing Corporation are funding the Queen's research on straw-bale homes.
MacDougall told the symposium that even though there are only about 100 straw-bale buildings across Ontario, the material is an excellent, low-cost and an environmentally friendly design choice.
The only problem is, in Ontario, there are no building codes pertaining to straw-bale homes. Anyone interested in building one has to obtain an expensive engineer's stamp to show the design is safe before they are able to obtain a building permit.
MacDougall said the more research done on straw-bale construction, the more likely it will become a more conventional building method. "We're really just scratching the surface," he said.
United Kingdom-based Mike Duckett spoke about his company's work with hemcrete, an environmentally friendly building material that combines hemp and lime. It's already used in various parts of Europe.
His presentation revealed the environmental and practical benefits of using the material, including the fact that it's sustainable, lightweight, a good insulator, airtight, easy to use, and fire and pest resistant. The material also absorbs carbon dioxide, one of the greenhouse gases.
Duckett said that each house constructed with hemcrete walls, roof and floors could reduce carbon dioxide emissions by 50 tonnes.
Hemcrete, which costs roughly the same as conventional building material, has been used to construct homes, office space, a warehouse and a theatre in Europe.
A building in England that has been touted as the most environmentally friendly warehouse in Europe doesn't require an air-conditioning system because the hemcrete material makes it possible to regulate the temperature inside at 14 C.
Hemcrete can be used to construct walls, floors and roofs in buildings that are made from steel, timber or concrete frames.
Duckett said that though it's not considered mainstream yet, he believes hemcrete has enormous potential to be used widely in the construction industry globally.
"What we know about this product to date is that it would work very well here in Canada," he said. "In the summer, it would eliminate the need for air conditioning."
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