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How to Build an Earthbag Dome

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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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Gabeuse25 days ago

My dreamhouse! I wonder how it could resist in a northem climate

Thank you Owen for all your wonderful information!
You have inspired my son and I to build a semi subterranean earthbag dome.
We have been hard at it for 2 months now and are finally getting close to the top.
It has been a learning experience to say the least!
Wanted to ask your opinion about waterproofing material.
Our plan is to have a living roof when we are done.
I am looking at the different materials available and it is all kinda confusing.
You suggested using 6 mil sheeting. Could we use recycled 5 mil tarps as we have no budget. Also what do you think of a light weight roof underlayment?
The material is a little pricier but would it offer any better protection from leaks?
We want it to last forever. Thank in advance!

http://www.lowes.com/pd_283849-711-5008030_0__?productId=3151833&Ntt=roofing+underlayment&pl=1&currentURL=%3FNtt%3Droofing%2Bunderlayment&facetInfo=

lsuydam5 months ago
I LOVE this. What do you think is the largest dome you could build this way?
Owen,
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.
Owen Geiger (author)  bthorson1391 year ago
This dome is too small to live in. It's really just a tool shed or emergency storm shelter.

I suggest making roundhouses. See my Roundhouse Instructable. It's easy to make roundhouses large enough for your needs.
I knew that hobbits would eventually take over the world.
Terralive1 year ago
Hi everyone. Does anyone know ho big in diameter I can buid an earth dome with an normal size bag:
Owen Geiger (author)  Terralive1 year ago
Somewhere around 20' interior diameter is about the limit. That would be 23' exterior diameter.

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
vsergeyev1 year ago
Thank you much for your prompt response :-). Yes, you are absolutely right that it is quite challenging to gain sufficient solar gain in cold and cloudy climates for any stryctures, including domes. For that reason I plan not to use short term solar gain chargers ( classical old school greenhouse) as it is proven not to be affective and sufficient. Instead, I am counting on the long cycle chargers ( the technique known as passive annualized heat storage). PAHS does not require greenhouse and lots of windows on the south side of the house. On top of that it utilizes the earth sheltering on the 3 sides of the structure. Thus I am confident a bermed earthbag dome must be the perfect solution to leverage the pahs technique in order to reach 100% off the grid sustainability. I have searched the Internet and did not find any bermed earthbag domes houses build in cold climates or bermed with a living roof except your little dome shelter. I am trusting 20" or 25" does could be bermed as well, yet, I have no practical and theoretical knowedge on how to design and analyze the earthbag structure to mate sure it could bear the top load of the soil as well as the side forces to the walls. My essumption is the dome must be adjusted to the 3 side berming loads. Ideally, the walks are to be built leaned outwards (likewise the retention walls).
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
Owen Geiger (author)  vsergeyev1 year ago
PAHS is an excellent system that should work well in your climate:
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.
vsergeyev1 year ago
Good day dear Owen. I admire your work and experience you put into all your earthbag projects. I am considering designing an earthbag home structure (consisting of a few 20-22" domes) for cold and cloudy climate of Ukraine (Eastern Europe) that I would like to berm it on 3 sides (with mostly windows / greenhouse on south side) and put a living roof on top of it. Ideally the house should take the best of of the earthbag / earthship / pahs/ life support systems to allow 100% sustainability and off the grid eco lifestyle.

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 :-)
Owen Geiger (author)  vsergeyev1 year ago
It's very difficult to get sufficient solar gain in cold climates with domes. You can't make too many windows in domes because all the weight is in compression and would weaken the structure.

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.
KMH1 year ago
Could I make a 20' diameter geodesic dome of steel pipe welded solid, and covered with re-bar/wire to support the earth bags filled with gravel/sand/cement/and a little water?
Owen Geiger (author)  KMH1 year ago
Yes, if you use lightweight fill material in the bags. Scoria, pumice, lava rock type materials work great. They're fast and easy to work with, lightweight, non-combustible, insulating and don't attract pests. Do not use regular earthbags on geodesic shapes or the structure would likely fail (unless you use a huge amount of steel to resist the weight, but that's not efficient). That's why earthbag and adobe domes look the way they do -- they use a shape that works with nature, sort of like an egg shell.
km213241 year ago
Can this hold a snow load of 7ft or over? I know everyone says its strong, but would hate to build one just to have it fail in the winter.
Owen Geiger (author)  km213241 year ago
That's nothing. There's around 20 truckloads of soil on top and the dome has never budged. You could put another 100 truckloads of soil on top and it still wouldn't budge, because of the nature of domes. The dome shape channels the forces down and away from the building.
I am so so curious, what does this look like inside? Could you post a few pictures?

Is it hard to live in there with cramped quarters?
Are winters unbearably cold?


Thanks!
Inside looks like white poly bags stacked like big bricks. The walls curve up to a point. It's only 8' wide at the base and so it's a little difficult to take photos. We use it for storing tools, and it works great for that purpose. You'd want to build a bigger dome for living -- say 16' diameter minimum. To determine the best size, simply put a stake in the ground, tie on a piece of rope and scratch a circle in the earth. That will help you visualize the space better.
Build a life size model of Bag End. Challenge Accepted.
No, no, no! Build a life-size model of Hobbiton, wait, no, The Shire!
Wait a second, is this why Bag End is called Bag End?
"The name comes from the farmhouse in the tiny Worcestershire village of Dormston, in which Tolkien's aunt lived. It can also be seen as a pun on "cul-de-sac" (literally, "bottom of the bag")." - LotR wiki.

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".
Oh, I know it's Bag(gins) End - I was just fooling around.
Precisely!
Of course. Owen Geiger's real name is J.R.R. Tolkein.
Do we need a specific size? i just would like to know before i order it, if some one could help me out asap that would be great :)
Owen Geiger (author)  BigDogDahler1 year ago
Everything you need to know is in this Instructable and/or the Mother Earth News article. You'll need 18"x30" bags (measured when flat and empty). Lots of people are now using poly tubes, mesh tubes and mesh bags -- all 18" wide.
ok thank you, so if i order just that size i should be fine? and how much do u think were actually used? would 500 be enough?
Owen Geiger (author)  BigDogDahler1 year ago
The article explains how many you need.
where do you buy your earthbags? im having trouble finding them cheap
Owen Geiger (author)  BigDogDahler1 year ago
Everything related to earthbag building is on our websites. Go to the Resources page at EarthbagBuilding.com
Do you think it would be possible to use a marsh clay for foundation bags, still with the rubble ground covering>??, because i live in South Africa and i do not have all of the necessary resources.?
Owen Geiger (author)  BLUEFOOable1 year ago
It's always best to use gravel in foundation bags so water can drain away. The foundation supports the walls above and so everything could collapse if the lower courses turn to mud.

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.
unleavened1 year ago
hi i saw this article and thought it sounded crazy - i've got to try it!
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!
Owen Geiger (author)  unleavened1 year ago
There are many possibilities. You have to investigate the options where you want to build. Maybe you have to add solar, etc. if you're off grid. Maybe you can tap into local power and water. But this typically requires following strict building codes. Codes vary considerably from place to place, so you have to investigate what local building authorities require. We typically recommend building in rural areas with few or no building codes to minimize costs.

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.
supershot12 years ago
how much are the earthbags alone??
Apparently there is a place where you can get 500 of them for only $75 but i wasnt able to find it. However I did find this website, but i dont know if i selected the right size, 500 of them comes out to about $160 which is fairly cheap.

http://www.onlinefabricstore.net/utility-basics/utility-supplies/sandbags/polypropylene-sandbags/14-x-26-polypropylene-sandbags-.htm
Apparently there is a place where you can get 500 of them for only $75 but i wasnt able to find it. However I did find this website, but i dont know if i selected the right size, 500 of them comes out to about $160 which is fairly cheap.
about 12 hours a day?
Owen Geiger (author)  theshedlife2 years ago
Not sure what you're saying. I sure don't work outside 12 hours a day. Most of my time is spent researching, writing and designing houses. The earthbag dome was finished a little at a time on weekends.
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