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Milkwood Blog

Earthbag dome, happy home

May 2, 2011 | Courses + Workshops, Natural Building | 15 comments | Author:

A couple of months ago we had the opportunity to build an earthbag dome at Milkwood Farm, and run a workshop while we built it. We jumped at the chance. We’d always wanted to try earthbag building, but where do you start with such a venture?

And so it was that over six days, Neil and Stella guided us and 20 other workshop participants through the dirty, intricate but surprisingly simple process of raising an earthbag dome from the soil of Milkwood. It was one hellava week.

Digging the foundations
Neil addresses the workshop after laying the foundation course of bags
Harris mans the compass to keep the course of bags on the level

Earthbag is a building technique we’ve been interested in for a while. The basic gist is that it grew out of experimenting with sandbags to erect crisis housing in disaster zones. In short, the technique involves filling bags with earth and/or other stabilizing material, laying them down and flattening them out, and using multiple layers to build permanent structures with excellent tensile strength.

The week we spent raising the walls of our first earthbag dome turned out to be as much about what happens when 20 people come together to build something, as it was about the actual structure.

For this workshop the group at our farm was formed of families, licensed builders, owner-builders, wanna-be owner builders, the curious and those who just wanted to escape the city for a week and do something (very) physical.

Getting there...
Workshop diagram explaining the construction of the domelet
Axel 'tamping' down the newly laid course of bags

So over these six days we collectively raised a building which will likely still be hugging the hillside at Milkwood Farm long after Nick and I are compost. The dome is made from the earth of our farm and will be a safe and warm little house (okay, room) for our guests for many years to come.

All done with earth, bags, gravel, barbed wire and a heap of collective effort.

I’ve decided that I’ll break down the specific stages of the build of the earthbag dome into separate articles so that, rather than just giving you a pretty slideshow, our experience can actually be of use. So from here on in you can go to the following link to get to the entirety of articles on this build:

www.Milkwood.net/tag/earthbag

More than halfway there now!
Making a window cavity with bags under pressure
More tamping. Tamp, tamp, tamp...

To report back on the build in general, however, it was… like nothing we’ve ever done before. Unlike our ongoing cottage build at Milkwood, this project was a concerted effort that raised the entire structure of the dome (except for the skylight) all in 6 days.

I loved the simplicity and elegance of the form, and the fact that, while the design and structural approach took some thought, it wasn’t rocket science. This is natural building at its best. Simple, effective, low embodied energy and non toxic. A room that is a pleasure and a balm to sit within.

This time frame also allowed for class time and design time, so if you were just focusing on building with a crew, I guess it would be a shorter build. The cost of materials will, by the time we are completely finished, be about $3,000. Note that this is the cost in raw materials – it doesn’t include labor, design or consultancy. But it’s a useful figure none the less.

The dome nearing completion
Hooray we've finished the bag part now...
Ashar enjoys playing in the domelet fireplace while he can.

The feeling inside the dome, which is being rendered as i write this, is one of solidity and protection. It just feels good in there. We’ll be putting in a small bed in the dome and a rocket stove in the domelet (i believe an ‘apse’ is the correct term for the domelet) to heat the inside space. It should be a wonderful little nook for guests at Milkwood sometime soon!

Stay tuned for Earthbag Buidling specifics, starting with building the foundations…

Some Earthbag resources:

Our earthbag dome with bagging finished and wiring done to put a ferrocement cap on the top bit for waterproofing
The view from inside: ah, the serenity...

Hooray to the entirety of our 2010 Earthbag Workshop crew, and to Neil and Stella of Guiding Star.



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15 COMMENTS


  • frann May 2, 2011 at 11:15 pm | Reply

    Great!


  • Michael May 3, 2011 at 3:03 am | Reply

    Friends and myself (came last saturday) were very impressed by this house… huge man-hour input… but considering how long it wills stand for, may still be economical in a sense.


    1. milkwoodkirsten May 3, 2011 at 1:17 pm | Reply

      Glad you liked it Michael! Yes there is a big labour input but I think it’s about appropriate use of energy.

      If you have lots of materials and one person, Earthbag may not be for you. But if you have 20 people and little or no materials, it might suit perfectly.

      Also there is the embodied energy of the structure to consider: some building techniques outsource that energy to materials, some techniques keep it close to the source and expend the energy as human labour… horses for courses, perhaps?


  • harry wykman May 3, 2011 at 8:42 am | Reply

    Hi Kirsten,

    Thanks for the great post. I’ve wanted to have a go at sand bag construction for a while too. Great to see it in action.

    Its the perfect technology for the sandy plains of Perth.

    Thanks again,

    Harry


    1. milkwoodkirsten May 3, 2011 at 1:14 pm | Reply

      Harry just FYI here’s a photo of a earthbag dome using sand in the sandhills of NSW south coast: http://www.facebook.com/MilkwoodFarm#!/photo.php?fbid=204077529618177&set=o.325427763800&type=1&theater


  • Jason Dingley May 4, 2011 at 1:39 pm | Reply

    What a beautiful organic looking structure. Did you make the bags?


    1. milkwoodkirsten May 4, 2011 at 3:39 pm | Reply

      Hi Jason, no we bit the bullet and got the bags from http://www.bundybag.com/ – but you can make them yourself out of any bag material you choose, if you have enough time!


  • Eileen Bernsrein May 7, 2011 at 1:48 am | Reply

    When I think how the poor live in Tijuana – wooden crates on the hillsides, where they freeze in winter. They would be so much warmer and secure in one of these than how they are existing at present. Or maybe, even simpler, if the sandbags were built up on the outside of their crates to provide warmth in the winter and cooling in the summer….


  • […] is the first post in a series explaining how we built our very first earthbag dome at Milkwood Farm. Earthbag is a natural building technique that uses bags of earth to build […]


  • moment to moment August 2, 2011 at 7:18 am | Reply

    Loved coming across this just now as we are getting ready to construct an Earthbag house in the jungle of Mexico. Also love all the resource links.
    It seems you guys are doing a lot of what we hope to do here at some point in the not too far off future..
    Blessings,
    Christina


    1. milkwoodkirsten August 4, 2011 at 8:48 pm | Reply

      good luck!


  • kevin o'brien August 11, 2011 at 2:46 am | Reply

    in regards to your cost estimate of $3000……………..could you give me a rough breakdown? i can see maybe $500 in concrete if you are stabilizing the earth, and also for the finish, $200 in tubes maybe, and $500 for windows , a door, plastic, formwork and barbwire. what am i missing in my math please?


  • […] Earthbag Dome, happy home […]


  • lauren September 29, 2011 at 9:01 am | Reply

    I love the idea. Does anyone know of the building codes and permits regarding Earthbag homes in Victoria?


  • Jan Zandvoort December 11, 2011 at 5:20 pm | Reply

    Hi there, good bit of reading about your earthbag dome, like Kevin here above I’m also very interested where the 3.000 dollar was spend on. Very interesting reading though. At the moment I’m in the process of making my own little rocket cooker for taking with us while we are camping. ‘My wife and I follow “Dancing Rabbit” and Lamma’s for quite some time. Love to life in a similar way but don’t see possibilities here in an over-crowded Holland.
    Keep up the good work!!
    Jan and Maud Zandvoort from a wintery Holland.



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