Note: If you’re new to earthbag building, first read the introductory Step-by-Step Earthbag Building Instructable and How to Build an Earthbag Roundhouse . Also, my new Earthbag Building Guide and Earthbag Building DVD are now available.
We built this earthbag dome at our home in Thailand for Mother Earth News Magazine in 2007. The article that describes the complete building process in detail was published August/September 2009. It is now free on the Internet: Low-Cost Multipurpose Minibuilding Made With Earthbags , by Owen Geiger.
This earthbag dome Instructable simplifies the process and illustrates each step of construction with photos. The two critical drawings are also included here. Please refer to the complete article before asking questions.
This multi-purpose dome can serve as a storage shed or cool pantry above ground, or as a rootcellar or storm shelter below ground. No building permit is typically needed, because it is below the minimum size required by building codes, is not inhabited and is not attached to a residence.
Earthbag structures provide a cool space in summer and an escape from the cold in winter (ideal for humans and animals), which means this earthbag dome is well suited for many purposes, like a quiet space for relaxing or playing music, as well as those listed previously. Depending on your needs, the most practical combination of uses might be a rootcellar/cool pantry for daily use and a disaster shelter for emergencies such as tornadoes or hurricanes.
The key concept that makes earthbag domes work is corbelling. This means each course (each row) of bags is inset slightly from the course below. Corbelled domes made of adobe and stone have been built for thousands of years. The concept has been applied to earthbags in the last few decades.
Basic project information:
18’ exterior diameter; 8’ interior diameter; 11’ exterior diameter, 50 sq. ft. interior floor space; total cost of materials: $300, which is about $6/square foot.
Tools:
Tamper(s), round nose shovel(s), grape hoe or grub hoe (digging tool), 13” x 16” sheetmetal slider, knife, hammer, 2’ level, 2” x 4” x 10’ leveling board, tape measure, fencing pliers, handsaw, trowel, garden hose with spray nozzle, 6’ or 8’ stepladder
The following instructions assume you have cleared and leveled the site, removed topsoil, positioned fill soil around the building site to minimize work, dug a trench to stable subsoil, put about 12” of gravel in the trench, and added two stakes with string lines: a center stake with string line to measure the radius, and a stake in front of the door to measure the dome curvature. Bags or tubes can be used. We demonstrate bags, because they’re often available recycled for very low cost. My YouTube Channel has a short video showing how the dome was built.
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Signing UpStep 1: Dome Plans
Let’s briefly take a look at the plans so you’ll better understand the building process. The first drawing is the floorplan that shows the dimensions for the dome base and the angled buttresses in front. The buttresses provide reinforcing on both sides of the door and also act as retaining walls to hold back the earth. Make a rubble trench under the buttresses the same as the dome, and interlock (overlap) each course where the dome and buttresses intersect.
The second drawing is the dome section that shows key vertical dimensions, earthbag foundation, door and arch. Note the wood stake in front of the door. The string line on this stake guides the curvature of the dome (112” radius in this case). This dimension remains constant. Put the stake off to one side of the doorway so you’re not tripping on it during construction.
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If I'm trying to make this dome for my cousins do you think it would be big enough? Or would it be better if I just made a roundhouse or regular one. I have a lot of cousins and I want there to be enough room for all of them.
I suggest making roundhouses. See my Roundhouse Instructable. It's easy to make roundhouses large enough for your needs.
The largest earthbag dome at this time is the Om Dome. It's 27' exterior diameter. They had problems and had to rebuild part of it. Don't risk doing a large dome like this unless you're experienced. The dome could collapse on you while you're building it.
http://www.earthbagbuilding.com/projects/omdome.htm
I would like to be sure of how to estimate the strength of the earthbag walls and the vaults (top of the dome) to make sure it is safe.
I would be very grateful to you if you could kindly share your vision, knowledge and experience on how to design such a structure.
Thank you once again for your kind support :-)
Yours,
Volodymyr
http://naturalbuildingblog.com/pahs-earthbag-house-near-completion/
http://naturalbuildingblog.com/pahs-earthbag-house/
I was suggesting 24" or so small berms on the sides, but you're wanting near 100% efficiency and that will take extra cost and labor. What I'm saying will work and be easier and faster to build. So in summary, you might want to do PAHS and south facing windows on a rectangular structure. Or bury earthbag domes and add a living roof. Both will work. One provides a more conventional appearance and more square footage. Domes are more organic, stronger and can be covered with as much soil as you want. In both cases take care to channel water away and add multiple waterproofing layers.
With these thoughts in mind, i would like to seek your kind support and anvise on how to design and ensure the strength of the structure to bear the topload and sideforces of the berm. Could you please kindly share your best considerations of how the shape of the domes must be adjusted to balance the external forces? Could the dome walls ,perhaps, lean onto the berm likewise the retantion wall do to counterforce the berm forces? What about the top part of the dome, should ut just be more tall? What shell be the rational on the shape geometry vs the size of the dome? Would there be any corelation? Thankyou very much in advance :-)
It's much easier to build a rectangular structure like the ones popular in the 1970's. The 'energy crisis' (oil embargo) back then prompted many designs and builders to come up with more energy efficient designs. With the passage of time we now know what works and what doesn't. This information is available for free on the Internet. The common characteristic is lots of south-facing windows for solar gain, thermal mass to absorb and store the heat, and insulation to prevent loss of heat. Earth-berming also improves efficiency.
See:
http://naturalbuildingblog.com/underground-houses/
http://naturalbuildingblog.com/pahs-earthbag-house-near-completion/
One spin-off of this research was Earthships. They have the south-facing windows and other features listed above, but also curved back walls to resist the thrust of the earth. The basic design works great. However, the plans are very expensive and ramming tires is slow and very difficult. Numerous builders have chosen to use the concept to make earthbag earthships. Search this phrase on our Natural Building Blog: http://naturalbuildingblog.com/
You can see a prime example on my Instructable -- How to Build an Insulated Earthbag House http://www.instructables.com/id/How-to-Build-an-Insulated-Earthbag-House/ This should work perfectly for you.
Is it hard to live in there with cramped quarters?
Are winters unbearably cold?
Thanks!
However, I do know of one project that used marsh mud successfully. This is NOT recommended, but in this case it did work. Build above grade (raise the site so water drains away quickly or build on high ground), use wide roof overhangs so water doesn't hit the walls, use plaster to deflect any snow or rain. Berming earth around the sides about 24" high would also help protect lower walls. I would only do this in a dry climate on a small house or cabin where no other options are available. Again, this is not good building practice. I'm just saying that sometimes you may have to break the rules out of necessity.
More to the point, it's also a slight pun on "Baggins", since if you say "Bag End" quickly as one word, it sounds not entirely unlike "Baggins".
i'm pretty hands on, but i've never done anything nearly as complicated or big as this - i'm a complete beginner. if i want to investigate this possibility, aside from a patch of land, what do i need to look into if i want to incorporate electricity, heating, water, bathroom facilities, and pretty much everything i need for a normal house? do i need planning permission? do i feed off someone else's electricity/water etc or do i organise it independently? (you can see i'm a real beginner!)
i'm living in israel where it gets pretty hot and pretty cold, raining quite a bit in the winter. i'd like to build a two bedroom house - got any suggestions? how long do you think it'll take?
cheers, this looks like the revolution of the century! my family will think i'm mad - i can't wait!
thanks so much!
Time of construction will vary depending on your skills and strength. Earthbag is very labor intensive. It's best if you're strong and healthy or can hire low cost workers.
Start with a small tool shed and take it from there.
http://www.onlinefabricstore.net/utility-basics/utility-supplies/sandbags/polypropylene-sandbags/14-x-26-polypropylene-sandbags-.htm
Dome plans are here: http://earthbagplans.wordpress.com/
(click Domes to browse only dome plans, or see all 130 plans)