Earthbag construction can be a wonderful way to build a small (or large) home. Earthbag domes are also incredibly simple to design and build. These little structures can be adorned with a living roof, or covered in mud or plaster. They are structurally sound, and when complete can blend into the landscape, thereby minimizing the effects on the environment. They’re also inexpensive to build and might be an option for those folks to build on a limited budget.
The earthbag dome structure below was built for Mother Earth News by Owen Geiger as an example of the construction technique back in 2009 for only $300. This dome could be used as a shed, shelter, above ground root cellar, or playhouse, among other things. With a little ingenuity and creative thinking, one can easily see how this type of structure could be scaled up to build a larger sized home. Read the original article below.
Low-Cost Multipurpose Earthbag Building: With this novel technique you can make an earthbag building to serve as a studio, garden shed, chicken coop, or root/storm cellar — no permit required! ~Mother Earth News
“Domes are the strongest form in nature and easily support enormous forces. We added about 20 truck loads of soil on the dome without it moving one bit. I’m confident another 100 truck loads could be put directly on top and it wouldn’t make any difference, because the dome is all in compression, and tamped earth (road base in our case) can support very high loads. So if you want to build underground, domes are a good way to go – that or roundhouses. Both gain their strength from the circle: forces (loads) are transferred directly to the ground. There are no components to fail as in post and beam or wood frame walls.”
Instructables – How to Build an Earthbag Dome
How to build an Earthbag dome
Owen Geiger simplifies the earthbag dome building process on his Instructables page, using the dome he built for Mother Earth News as an example. The first step is the plans, which are not only necessary when considering space and materials, but also help to understand the building process.
After the plans are determined, the ground is leveled and prepared for the foundation bags. The foundation layer uses double-bagged gravel to prevent wicking moisture into upper layers of bags. Soil is then tamped around the foundation layer to hold it in place.
A string line from a center stake is used to ensure each level is a perfect circle. The radius of each level is slightly smaller than the preceding level.
Every course is tamped and leveled before moving on to the next course.
Barbed wire is placed between each course to help hold the bags in place.
In this dome, tires are used to form the window.
Earthbag domes are most often finished with plaster, but the builders opted to put a living roof over this one, which requires more maintenance, but looks beautiful.
The front entrance of the dome is finished in yellow-pigmented plaster. This dome, in the builder’s yard, is used as a tool shed.
Kind of reminds you of a Hobbit house in the Shire, right?