Strawbale homes
With the increase in sustainable buildings and a seemingly exponential increase in product development, I was recently asked about strawbale houses, so I thought it was worth revisiting strawbale construction to see where it sits in 2022.
Firstly, building a house in Australia will require complying with numerous regulations and standards. A number of these are aligned to typical veneer construction methodology, i.e. an internal structural frame with the external cladding (think your standard brick house, where the bricks are just skin and carry no load except their own). When you build with Strawbale, Hempcrete, Timbercrete, Mudbrick, Rammed earth or SIP's you are working outside 'the box', so you will need to be prepared to hear a lot of 'it can't be done' or 'why would you do that. In return, though, what you get is a beautiful, handcrafted sustainable home.
A strawbale house may cost the same if not more than the conventional house, with strawbale walls themselves only making up 14-20% of the total cost of a building. (https://houseofbales.com.au/q-and-a.html) They are typically built like giant bricks attached to a frame, finished with a heavy coat of render to protect them from the elements, which gives them their distinct shape.
The bales themselves are construction grade, meaning you are generally not getting them directly from the farmer next door. Like clay and mudbrick houses, moisture levels and compaction are critical to ensure a quality end product. But unlike these houses, a strawbale is typically using a waste product.
Design: You are essentially building with an oversize brick. The designs have similar constraints as clay brick, like moving between Lego and Duplo. The primary advantage of a strawbale design is its thermal properties. A typical straw bale wall has an R-value greater than 7 (https://www.yourhome.gov.au/materials/straw-bale) significantly greater than clay, mudbrick or even hempcrete. Therefore it lends itself to energy-efficient or even passive home design. The construction method is pretty straightforward, allowing owner-builders or community groups to enjoy creating a shelter. Its distinct wall thickness allows for a roundness to the wall and a gentle aesthetic contrasting against many of modern architecture's hard, sharp lines.
In summary, when complete, a strawbale home will have significant annual energy savings through high insulation to the external walls. It makes use of a waste product and unskilled labour. While unlikely to be a frugal build, it provides a unique aesthetic and artisan quality that appeals to many.
Reference:
https://www.yourhome.gov.au/materials/straw-bale
https://www.hempcrete.com.au/
https://www.postbeam.com.au/building-materials/strawbale-building
