Earthbag is the quickest, easiest and most forgiving natural construction material you can build with.
Any earth construction method is hugely rewarding for a variety of reasons – however there’s a technical aspect to most earth techniques that can often feel overwhelming. How to understand what soil type you have? How to know what ratio of sand and straw to mix it with? Load bearing or non-load bearing walls?
This is where Earthbag (or Superadobe) really comes into it’s own, and why a weekend workshop is so useful – so you can learn by doing. Patrick & Alaia attended one of our garden wall building workshops in 2019 and decided this was the technique for them – and Pat’s Earthbag Dome House has been the result.
During a weekend workshop held earlier this month – amazingly between several regional NSW regional lockdowns – Pat’s 3.5m diameter Dome House started construction with a wonderful group of new earth builders from around the North Coast of NSW.
Pat had already prepped the site and dug the ‘rubble trench’ foundation, so this meant the participants could come in and start by filling the trench with local rock, and then creating the ‘stabilised earth’ first layer.
After months of seeing no rain, the earth stockpile was quite hard, however with a good soak even the hardest clay will break up. After that it is relatively easy going, and many subtle tricks and techniques were taught over the two workshop days.
The end result will be a type of ‘beehive’ dome with large entry doorway, some smaller circular windows, and a lime stucco plaster externally. We also added in a glass bottle layer, to give a beautiful lighting effect once the dome is finished and rendered.
Using Earthbag as your main earth-building material, especially if it is almost pure clay like the Pillar Valley earth, will give you incredible thermal mass – which is ideal for our temperate – sub-tropical climate. With a resulting wall thickness of approximately 45-50cm you create a time lag of around 12 hours from the external temperature to internal temperature transfer – which essentially means you can maintain a constant temperature night and day. Domes also create a type of ‘funnel’ effect, sucking cooler air in from the lower level and venting hot air out of the top of the dome, along with ‘breathing’ and regulating the humidity internally – which keeps you feeling very cool and comfortable in the summer months. Earth structures due to the density are also natural EMF shields – more and more important these days.
We had a lot of fun over the weekend – there is truly no better way to connect with each other than by being outside, working with the earth beneath your feet, and working together to achieve a common goal. As Alaia noted towards the end of the second day “it was just so wonderful that the only sounds you could hear were people chatting. No machinery, no electrical tools disrupting the atmosphere.” Just the odd curious kangaroo…!
We will post updates as Pat starts to close out his dome, bag by bag! So far this was 10T of earth moved & 250 onion bags. Big effort and big result.