Any Grand Designs or Kevin McCloud devotee will tell you the production of concrete is a terrible burden on the environment (they are also likely to wax lyrical about the ‘art’ of good design and wear a pin-striped woollen blazer). Straw, on the other hand, is cheap, a great insulator, and generally much more ‘green’. So, with little in the way of downsides, why is it that we don’t see more straw houses being built?
It sure gets Mr McCloud’s vote, but straw housing seems to have become the dominion of slightly quirky self-builders and pot-bellied pig farmers on small holdings in the United Kingdom. However, considering the housing and energy crises facing Australia at the moment, this age-old building technique is slowly making a resurgence; thanks to the likes of Dani Austin, Sam Ryan and their kin, who aren’t afraid to buck the trends.
Sam and Dani, a young couple from Adelaide, hope to move into their new straw bale home within a few weeks, and spoke with the ABC about their enthusiasm for this particular building material.
As Sam explains, they took quite a while to decide where they’d like to build a home, and also struggled over how they would construct their house.
“We settled on a more sustainable, traditional, but perhaps unconventional build,” says Dani. “So that we can be involved and it will save us money now and in the long run.”
Now, house almost complete, Sam and Dani are pleased with the results. Sam has, in fact, pledged to lend his hand to any other straw bale building projects that come up in the area, after receiving so much help with his own build. As keen advocates for the straw bale building method, Sam explains how they came to reach the decision:
“We decided to go for straw bale for lots of reasons, but certainly how easy it was to do ourselves, and to get our friends involved. And the cost of the baling is quite low, it’s the labour that costs the money,” says Sam. “Another reason that we chose straw bale it its incredibly high insulation value.”
The benefits of straw bale
Because of the relative affordability of straw as a building material, many assume a straw bale house will come in well under the cost of a traditional build. Despite this however, the intense labour involved with building in straw can dramatically increase the construction costs involved. Luckily for Sam and Dani, they have a willing team of volunteers who are keen to learn the tricks of the straw-building trade and pitch in with some blood, sweat and tears. For the keen self-builder, this technique represents a real opportunity to save on labour by getting your hands dirty. Paying a professional builder, who specialises in straw bale, is another matter entirely, and will require a rather larger investment.
While the building costs are largely dependent on whether you choose to self-build or not, the insulation value of straw bale housing is without a doubt it’s most attractive quality for home owners. Straw bale construction can reduce the need for traditional heating and cooling significantly, and in some cases, can negate it entirely. Finished with cob (a mixture of mud, straw and water) walls, and rendered, straw bale structures can function with little to no heating and cooling, even in the harsh Australian climate. Reducing power bills significantly, this is an investment that, over time, pays dividends.
Limiting household consumption of power is not only great for the occupier, but for the environment at large. As our climate heads steadily towards a 2°C+ rise in coming years, it is imperative that both the residential and business sectors reduce their contribution towards greenhouse gas production. The environmental benefit of straw bale construction on carbon emissions is two-fold. Like timber, straw has an incredible ability to store carbon from the atmosphere and effectively build static carbon-stores when used in building. While its thermal mass reduces power consumption within the home, the very production of straw reduces atmospheric carbon. Furthermore, straw is an agricultural bi-product of grain-growing, and therefore its production doesn’t detract from important food crops—it is, in fact, renewed with every harvest (annually), unlike timber. It’s the very definition of a win-win situation for builders and the environment.
The Three Little Pigs
Sure, straw bale houses are a plethora of greeny-goodness and will save all the possums in the land. But—and there is a ‘but’—there are downsides. Despite the experience of the Three Little Pigs (come on…there’s no way we could not mention those guys), straw bale structures, when built well, are incredibly sturdy. Nevertheless, straw does present some challenges as a building material, not least of which are the threats of mould, bugs, and rodents. If not left to dry properly, or if regularly exposed to the humidity of wet-rooms, straw can soon mould and decay. So long as these areas are properly protected however, it is possible to avoid these shortfalls.
Another issue facing straw bale homes is that of thermal breaks, which occur if bales are not stacked properly. Self-builders with no experience in this construction method may soon find their home subject to unexpected draughts, and again, face the dreaded mould. Proper construction of straw bales must avoid breaches in the stacking of bales, as well as in the rendering process. The insulative properties and longevity of these structures rely heavily on their precision construction.
While these hurdles are able to be overcome, perhaps the primary reason for lack of interest in straw bale housing is the sheer amount of space these buildings require. With walls as wide as 500ml, straw bale houses are no solution in the space-poor environments of apartment blocks and suburban housing plots. For a standard 3-bedroom construction, a straw bale house will represent a significantly larger footprint than a conventional wood, steel or concrete structure.
Another challenge to overcome is the hanging of pictures and frames, which is quite a challenge in your typical straw house. Due to lack of studs in the construction, the ability of the walls to hold artwork, mirrors, shelves and the like is severely restricted. While there are solutions to this particular problem, they require no small measure of ingenuity and compromise.
As energy prices rise, and housing affordability continues to be an ever-increasing issue for Australians, straw bale construction certainly presents a solution worthy of further investigation. For couples like Sam and Dani, the befits have outweighed the difficulties. Spending a mere $350,000 on their land and house construction combined, it seems as though they’ve hit upon a real alternative to the typical outer-suburbs, energy-guzzling new build which many have opted for. If the movement gains momentum, we may soon see the niche straw bale construction industry grow to more mainstream proportions. Most of the issues presented by straw bale builds can be overcome by precision construction and a little forward-planning. We may yet see straw bale become the next trend in affordable housing for a market which is quickly becoming exclusive to foreign investors and baby boomers. Kevin approves.