According to wise Wikipedia, “natural building involves a range of building systems and materials that place major emphasis on sustainability”.
Our house in Katoomba, while we loved it, was not at all efficient or sustainable. It was poorly insulated, had single glazed windows (and lots of them) and didn’t have great air flow. Before Master Wolf was born, we installed gas ducted heating, and while it made the house more comfortable, especially with a newborn, it was extremely expensive to run. The large windows in the living room were east facing and let in a lot of heat in summer, and due to the layout of the house it was difficult to get any cross breeze.
In thinking about building methods, we wanted to build something that would cost very little to live in. This meant thinking about solar passive design to harness heat energy from the sun, a window/door schedule that would enable air flow and materials that provide good insulation.
In terms of insulation value, it’s hard to go past straw bale. A typical insulation value required by BASIX (the building sustainability index for Australia) would be R2, whereas the R-value of a straw bale wall is between R8-10. This would mean that the house would be cool in summer and would keep the heat in winter (and would provide some noise insulation for Papa J who has very sensitive hearing).
We also considered mud brick as Papa J’s dad had a beautiful handmade mud brick home in the Southern Highlands and it was really lovely to stay in. We decided against this as the requirement currently seems to be that you need to build with a double skin of mud bricks, even though this is unnecessary due to its excellent thermal mass.
In essence, it was really important to us that our house be designed to fit in well with its environment, to be well-thought out to minimise energy consumption and to use natural materials. Straw bale building fit well with this as it uses a waste product (straw), wood and natural lime/clay render to create a really efficient and comfortable home.