Dr. Kris Dick speaking at the Canadian Hemp Trade Alliance national convention in Winnipeg last week.
A Biosystems Engineering professor at the University of Manitoba says buildings made with straw have come a long way from the days of the three little pigs.
Dr. Kris Dick is the director of the U of M's Alternative Village , a small collection of straw-based buildings, sheds and huts used for research on the university's campus.
"Use of straw is increasing, certainly on the owner/builder side. Now there's certainly more of an interest in secondary manufacturing of that straw and using it in other products such as panels or hempcrete," he says.
"We have used wheat, oats, barley and hemp but the preference, from a building material perspective, is on wheat and hemp," he says.
As with any building system, Dick says the keys for a solid straw building are a proper foundation and roof design.
"You have to pay attention to detail. Your building should have good boots and a good hat and proper detail to the design. You have to manage the moisture as it comes. So that's not unique to straw bale, that's any kind of building system."
He notes most newly-built straw buildings are still based on the two-string small square bale.
"You can either have the straw be load-bearing where the straw and the plaster skin take the load. Or it can be used in an in-fill system where a structure takes the load and the straw, with the plaster on it, resists the moisture, wind loads and provides insulation."
Could we ever see mass-production of straw-based buildings? Dick says consistency is a challenge.
"Every straw-bale house you could argue is a custom home. If we're going to take it from using two-string bales to something that's more mainstream, I believe we need to move into more of a modular type of system where we may be manufacturing that in a plant where we would have more control...right now, if you asked someone to define what constitutes a 'good' straw bale versus a 'less good' bale, it's based on the experience and opinion of the builder," he says.
~ Tuesday, November 23, 2010 ~