The Permacultivator - Journal of Cool Climate Permaculture
Do you remember the story of the Three Little Pigs - in particular, the first Little Pig who has his house of straw blown down by a huffing and puffing Big Bad Wolf? He obviously didnt build his house from straw bales with reinforced steel rods holding the structure together and stucco render making it fire and wind proof. If he had it could still be standing today!
Information taken from a publication by Leo Newport (founder of the Merrigalah Project, and a straw bale housing advocate) tells us that in the USA (where he has recently spent some time) they have been building them for over a hundred years on the prairies (lack of trees made conventional building practically impossible). In fact there still is an occupied straw bale house in Nebraska which was built before 1910, and there is such a renewed interest in this type of housing at grass roots level that people have begun building them again.
If you are like me, you may be curious as to the construction of such a house. Here is a brief summary of the stages of construction:
1. A concrete slab is laid.
2. If you choose the design with a wooden post and beam framework, this is erected next. (The other choice is simply to rest the roof directly on the strawbale walls.)
3. Straw bales are then laid in the same manner as bricks would be (staggered along the line) with each bale being spiked twice through to the bale below.
4. Wall openings are protected by load bearing lintels over doorways and windows.
5. A concrete bond beam is poured on top of the wall ( or a timber wall plate is added) and high tensile wire/chains bind it to the footings for stability, then the structure is allowed to settle.
6. Wire mesh is used to cover the straw interior and exterior before being rendered with concrete or stucco.
7. The roof rafters and beams are then added and clad with whatever roofing finish is required.
Why build a straw bale house?
There appear to be some very good reasons! To start with, straw is a sustainable, low-cost building material.
The building technique, relative to conventional methods, is a simpler process which can be more readily undertaken by owner-builders and friends after a 2-week practical course. This has been shown to result in the subsequent saving in building costs of between 40-50% compared with a similar-sized conventional type of house. An additional advantage living in a straw bale house is that they are very economical to heat or cool due to the thick walls. Straw bale is estimated to provide an insulation factor of around four to five times that of fibreglass insulation in wood framed houses.
But, by far the most important factor in my opinion is the low environmental impact of straw bale. These houses are built from a waste products of a variety of primary industries (wheat, rice, oats, barley, rye, flax, etc) which would normally be burnt. So, not only are we releasing into the atmosphere tonnes of carbon dioxide (30,000 tonnes in NSW rice growing areas alone last year!) as well as solid particle matter (2,000 tonnes of rice ash last year), in the process of getting rid of the waste straw, but we are continuing to import foreign timbers and logging millions of tonnes of native forest timber each year to supply the building industry.
The Way Forward
As with the rammed earth and mudbrick technology, strawbale could be a possibility for future trends in environmentally responsible housing - using readily available renewable materials; a grain crop takes only one year to produce straw where native forest timber takes, on average, a minimum of 40 years! Although a change in conventional attitude towards use of renewable materials and energy in house construction is a slow process, it seems to have to start at the grass roots level for it to become part of mainstream thinking. Although this type of housing has been used in China, Russia, Canada and the USA, it is a new concept in Australia and hence no official testing has been done. As a consequence, local councils will no doubt put applications for strawbale houses into the too-hard basket.
Dont be put off! says Leo, who has founded the Merrigalah Project to raise the required $60,000 needed to fund the CSIRO testing over a one-year period on the straw bale house he is constructing near Armidale, NSW. Once the exhaustive testing program is completed, and if results show it to be safe and viable, then accreditation will follow and councils around Australia will then have guidelines to follow when approving straw bale housing construction. The first Little Pig could then apply for a new strawbale house!
Want More Info?
If you would like to have more information on straw bale housing you can contact Leo Newport on (02) 888 9708 or write to him at PO Box 602, Ryde, NSW , 2112.