By Matthew Charles-Jones Matthew is a member of Yackandandah Sustainability
Straw bales may offer a beautiful solution for those planning a new home or extending an existing structure. There are many examples of people creatively using straw to construct garden walls and decorative features using straw. Bales can also be used to great effect in commercial structures.
After much thought and reflection, my wife and I chose straw bales for our new owner-built house. Straw is a terrific building material for a whole variety of reasons that I will outline below. Beyond that, it is a great choice for owner builders as the width of a bale and their variance in size make it more acceptable for lines to not be exactly straight!
Straw bales can be used to support the weight of the roof (load bearing) or alternatively as the cladding around the structure holding up the roof. Typically the straw is then coated in multiple layers of render made using sand, clay and lime.
One really nice aspect of straw is that it can be regarded as a waste material from cropping and thus does not impose the environmental impact of new materials. Better still, if the straw is sourced locally it helps keep transport costs and associated carbon emissions low.
Commonly people use wheat or rice straw for construction purposes but any range of crops can be successfully used. Importantly the bale needs to be tightly packed and should not get wet – moisture and mould are a real danger for straw bale.
Straw provides a great insulative cladding material. Depending on the research used, some argue that a bale represents an R9 value when combined with a mud render. This then supports a home that can maintain a constant temperature especially when coupled with well placed windows, well designed eaves and thermal mass – heavy materials that will hold an even temperature. A straw house can offer a special feeling of calm and quiet, as they tend to dampen inside and outside noise.
Straw also provides a wonderfully flexible building material that allows shapes and designs that are difficult to achieve in more usual building products. This ranges from lovely wide windowsills and gently undulating walls through to spectacular sculptures and shapes.
So if you are thinking of a renovation or new construction, perhaps consider straw as a means of creating a healthful, well insulated and comfortable home.