Earthbag dome going up at the Permaforest Trust Farm in Northern NSW

Under the expert guidance of Neil and Stella from Guiding Star, we’re holding an EarthBag Building Workshop at Milkwood Farm from Feb 27 – Mar 5 this year. We’ll be building a 2.5m wide dome with mezzanine level, which will be perfect for cozy guest accommodation or a root cellar (we’re still deciding which). Bookings and more info here.

The reason I’m getting so excited about Earthbag is that by the end of this 6-day workshop, we should have all the knowledge and skills we need to go ahead and build earthbag structures by ourselves. And any building technique that can be taught from start to finish in only 6 days is one i want to learn!

Neil of Guiding Star on top of a multi-dome project in Mexico

It hurts to say it out loud but it’s now 4 years since we arrived at Milkwood, and we’re still not yet living in our tinyhouse above the dam in the middle of Milkwood. From conversations with other owner-builders (with only occasional weeping), I know this is not unusual. Life gets in the way. Livelihoods must be made, babies birthed, art created, opportunities taken. Still, I think when we finally move in (before this winter? fingers crossed!) i will be so completely happy i may just explode.

I think it was the indomitable Jackie French who said when building your own house, keep in mind that to accurately calculate the time it will take, you take your best estimate and then times that by somewhere between 6 and 10.

Mezzanine floor going in, with cute windows below

I know that the reason our house is taking so long is because there are so many new skills to learn, so many bits we need to find an expert for, and so much materials sourcing to do in order to keep the build footprint as low as possible (recycled timbers, 2nd hand everything, non toxic, bespoke bits and pieces, and so on) while keeping the price down.

Multi-dome earthbag house going up in Iran : image: Nader Khalili

Earthbag building, however, requires basic and low-input materials like earth, bags, lime or clay, and whatever doors and windows you choose, plus a few other basic bits and pieces. And that’s it! It sounds like heaven! True, it takes a lot of physical effort, but so does building a house any way you do it. So we’re going to give it a try.

The benefits of earthbag (or superadobe) structures are many:

Diagram of earthbag dome room with windscoop for airflow

- The huge thermal mass of the bags creates a very stable internal temperature, which can then be controlled by high or low air vents and appropriate siting for the climate. This makes them very comfortable to inhabit, especially in places that experience large temperature fluctuations. It also gives the room within a great sense of safety and solidness.

- Because of the materials involved, earthbag structures can be constructed prettymuch anywhere you like, including hard to get to places, as there is no need to cart a large volume of building materials to the site – you just need the bags and some other basic bits, and you can create the structure from the surrounding earth resources you have access to once you get the the site.

- The basics of the earthbag process is teachable (and learnable) in a very short space of time, because of the simple nature of the structures components. After 4 years and counting, any simple natural building technique i can learn from start to finish in a relatively short space of time gets the thumbs up from me!

A testament to the strength of this type of structure - everyone can just sit on the wall as it goes up (!)

- Earthbag structures can easily be made to be load bearing. This is a big one. Just ‘throwing up’ some posts so you can build a load-bearing mezzanine safely is no small thing in post-and-beam building, i’ve learned. But with earthbag, particularly earthbag domes, not a problem.

A little dome Neil and Stella made in a workshop for a community garden

- Earthbag structures are achievable. This is the biggest factor, in my mind. Like the permaculture principle obtain a yield, there is a huge emotional benefit in finishing a small and solid structure well, in a timely fashion. It gives you heart to make another one. It makes your family happy, and allows them to believe in your crazy non-standard building ideas.

And it gives you somewhere dry and comfortable to make that cup of tea while you plan your next natural building project.

Windows can be easily accommodated in whatever shape you like...

Some resources:

• Earthbag building in Gaza – video via Al-jazeera
• Simple domes, complex domes and other structures – at EarthbagBuilding.com
• Sandbag shelter housing in Iran – scroll down for some great pics
• Earthbag building Blog – lots of updates on materials and projects
• How to make an earthbag dome – pdf put out by the Permaforest Trust
• Cal Earth – the Californian Institute of Earth Art and Architecture
• Guiding Star Creations – our fearless teachers in the great Milkwood earthbagging!

At the core of this exercise, i see earthbag building as an extremely useful technique that would be good to have in my swag of skills. Every home, property and community has different needs and perameters for its built structures, but this is one of the few building techniques that can be realised regardless of wet weather (sometimes very important), with literally what lies around us. And i think that’s a powerful skill to have. So bring on the earthbag, in workshop form, and beyond.