Instructables
Note: If you’re new to earthbag building, please read the introductory Step-by-Step Earthbag Building Instructable first. Also, my new Earthbag Building Guide and Earthbag Building DVD are now available. Stay up-to-date on all the latest earthbag news by following our Natural Building Blog.

We built this earthbag roundhouse in 2010 as part of an earthbag workshop in Thailand, and finished it later that summer. Roundhouses are perhaps the simplest, fastest, easiest earthbag structure to build. We’re extremely pleased with the results, especially in terms of strength and cost. This is one of the strongest structures I’ve ever worked on in my 30-plus year construction career. The main impression is one of incredible fortresslike strength - massive walls with no sway. I’m sure it could easily withstand a direct hit by a speeding vehicle. This is no exaggeration. There’s been at least one incident where a drunk driver hit an earthbag wall and only chipped the plaster. (The vehicle was totaled.) Earthbags also excel at withstanding floods, hurricanes, tornadoes and earthquakes. Engineered plans are now available for whatever conditions you face. Earthbags are even bullet resistant, as explained in our highly popular blog post where compressed earth withstood 50 cal “BMG” 661 grain Full Metal Jacket rounds. Bullet Resistance of Compressed Earth

The other key advantage of earthbag is cost. For our roundhouse, we wanted things to look nice, of course, but we didn't want to spend a fortune. The final cost came out to $11.50/square foot. Most stick-built houses are $100/sq. ft. and up, so this roundhouse demonstrates how anyone can build their own home even on a very tight budget. We used a few basic, low cost methods to class up the roundhouse: rounded window and door openings (free), nice colors (no extra cost), curved bathroom wall and buttress (no extra cost to create curves), exposed wood and thatch roof (dirt cheap), earthen plaster on the interior (really dirt cheap), and lots of beautiful old windows for views, ventilation and to add a sense of spaciousness. In summary, build small -- just what you need, use simple shapes, pay with cash, and add on later if needed.

Basic project information:
18’ exterior diameter; 15’ interior diameter; 177 sq. ft. interior floor space; total cost of materials: $2,045, which is about $11.50/square foot

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, buried any utilities, put about 12” of gravel in the trench, and added a center pole with stringline to measure the radius. Bags or tubes can be used. We demonstrate bags, because they’re often available recycled for very low cost. My YouTube Channel has short video clips that show each step of construction.

 
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Would Lime plaster work well on the exterior walls? Or gypsum plaster? I'm in Central Oklahoma, by the way, with our weird weather patterns. Long dry (as in no rain) summers with high humidity, moderate winters with fairly low humidity, and two rainy seasons... spring being the main one, the second being in the fall. Clay soil, so flooding happens easily and slab built buildings usually do flood.

Leigh
Owen Geiger (author)  urbangleaner562 days ago

You can use cement or lime plaster. Some mix the two. Recipes are free on the Internet.

Owen Geiger (author)  urbangleaner561 year ago
Lime plaster is great. Read up on the details and follow the instructions.

Raise the building site above flood stage. We did this by dumping truckloads of road base in 6" layers and driving a truck back and forth over the top in opposite directions.
On the floor... if using earth floors, would I need to put down a moisture barrier, between ground and scoria, possibly tamped sand also? I'm concerned about moisture wicking up the walls from the ground under the floor. Our heavy clay soil doesn't drain well, and I have enough health problems without adding mold in the house on my walls to the mix.

Leigh
Owen Geiger (author)  urbangleaner562 days ago

Yes. Add a layer of sand and then plastic sheeting and then do the floor. That will prevent moisture from wicking up into the floor.

Owen Geiger (author)  urbangleaner561 year ago
Yes. Use typical plastic sheeting, also called 6 mil poly.
J-Ri9 months ago
This is absolutely amazing! I think I'm going to give it a try.

Do you know how these homes are affected by strong vibrations? I like to crank up my music sometimes and my current home shakes quite a bit when I do... I'm not sure if the heavy walls would be unaffected or if the dirt walls would crumble.

Thank you so much for the instructable and a reply if you have time!
Owen Geiger (author)  J-Ri2 days ago

No problem.

Owen Geiger (author)  J-Ri2 days ago

Don't worry, the walls won't vibrate or crumble. The walls are incredibly strong. The army uses similar construction methods (sand bags) to store loads of ammunition. The ammo bunkers are next to each other. If one bunker blows up, the other bunkers won't blow up.

kruklanki1 year ago
Hello Owen
Your building methods are astoundingly simple and effective – they just make sense. I live in Thailand and I want to build an earth bag roundhouse, a larger one that the 177 sq ft that you built here. I'd be interested to know where in Thailand you built the round house? Also, and more to the point, your mention of the materials being $11.50 per square foot was that the price in Thailand?

Thanks
Peter McLaren. Udon Thani
Owen Geiger (author)  kruklanki2 days ago

Yes, that's the price in Thailand. I live in Isaan.

Owen Geiger (author)  kruklanki1 year ago
You can email me at:
naturalhouses [at] gmail dot com
kruklanki1 year ago
Hi Owen
I find your ideas very inspiring
I intend to build a big roundhouse about 33 feet diameter in Udon Thani Thailand. It seems to me that the roof will present a problem in that I can’t think of any cheap material to build it with. I don’t want thatch because of the insects and the short life span of such a material. I actually want to include a central pole/tree trunk as an interior feature rather than using a compression ring.
I can get bamboo for next to nothing and cover the roof with it which should look good from the inside but I’m at a loss then to know how to waterproof it on the outside. I don’t want to have to screw tiles to the bamboo if I can help it.
I also want to build the site up with soil to about half a metre AFTER I build the house. So I think I need a solid foundation. If I make the foundation slightly higher than half a metre and us earth two bags side by side where do I place the single earth bags for the walls…….in the middle of the two?
Owen Geiger (author)  kruklanki2 days ago

I hope you see this. It's been a year already. We replaced our thatch with MCR tiles (super popular in Thailand). They should last 25-30 years. They're quite easy to work with. I would build a wood pole roof structure because bamboo in Thailand is too unpredictable unless you've thoroughly done your research and treated the bamboo.

Lower walls for earth berming: You could use regular bags all the way if the berm is only 24" high.

Owen Geiger (author)  kruklanki1 year ago
Foundation: Set the center post first then start your walls. Use doubled gravel bags or tubes (one inside the other) for added strength. Make sure you start on solid ground because earthbag walls are very heavy. Make a rubble trench under the wall. Do half a meter of gravel bags and then add fill material on the inside and outside. Road base is an excellent choice. Slope the ground away from the building in all directions. This will give you a raised floor. Do one more course of gravel bags before starting regular soil filled earthbags.

Roof: You can use bamboo, wood or metal framing. Bamboo is rather difficult to work with and requires treatment to prevent rot. It's not commonly used in Thailand and you'll have a difficult time finding what you need. Metal framing is actually a good choice in Thailand because it lasts a very long time and is affordable in Thailand. (It's the standard construction method now.) For roofing you can use metal roofing (often the best choice), micro concrete tiles (can still collect roofwater but not so noisy), wood shakes (hard to find) or ferrocement. You can email me at natural houses [at] g mail dot com for further details.
wwylde1 year ago
Any success with structure shapes besides "round"? Can you free form the design in a fashion similar to the "super adobe" style or . . . ?
Also: what kind of size/span limitations have you encountered with this method?
Owen Geiger (author)  wwylde2 days ago

Lots of people are building free formed structures. Curved walls are very strong. You just have to plan carefully so the roof isn't too difficult.

bandara9 months ago
Very interesting and very beautiful low cost house.
Owen Geiger (author)  bandara2 days ago

Thanks. We added new MCR tile roofing and it looks even better.

njc1219837 months ago
I have to say that I'm very impressed with your earth bag structure. Your explanation of the process is clear and concise. I will definitely utilize this "ible" when I need to add on to my current domicile.
Owen Geiger (author)  njc1219832 days ago

Thank you.

HydePoison4 months ago

Is it possible to go into more detail about plumbing and electric? I'm a bit confused about how that works in an earthbag home :/

Owen Geiger (author)  HydePoison2 days ago

99% is the same as any house. Check out the simplest books you can find from the library. I like the little "pocket guides" that are mostly illustrations. You don't need all the complicated stuff for a simple house. The small differences are explained on our Natural Building Blog (search by keywords such as electric) and in my earthbag ebook.

kcline23 months ago

From start to finish how long did it take and how many.

Owen Geiger (author)  kcline22 days ago

The walls took about 10 days. The roof was one day. (We replaced the thatch with MCR tiles after 3 years.) The plaster was slow. In total everything took around 2 months or so.

sparkyte16 days ago

I work a little more than minimum wage. A building probably 400-600 square feet is all I'll probably ever need. I really wish I could find someone like yourself to help me construct a fantastic building with similar material. I love the idea of thermal mass as opposed to insulation.

Owen Geiger (author)  sparkyte2 days ago

Natural building is quite basic. People have been building their own homes with local materials for many thousands of years. It's even easier now with tons of free information on the Internet. Do the research and plan carefully and you'll most likely be successful. Get a little help here and there if necessary. For instance, you could hire 1-2 carpenters to help on the roof or someone to help with the electrical. Our Natural Building Blog has over 2,000 blog posts now with lots of free information.

mike363204 days ago

I am working on getting ready to build some earthbag houses in the U.S. In the smaller towns they will allow them. You need to go to the planning and zoning dept and talk to them and give them the plans and just talk to them. If you comply with all the electrical and plumbing codes and allow the inspectors to see it and show them the process and let them see it will be a solid structure. We will be using metal roofing for our houses. All I know is work with them and they will work with you.

Owen Geiger (author)  mike363202 days ago

Yes, that's right. Many places will. Things will vary place by place. Building departments might be more accepting/more lenient now due to the housing slowdown. Every new home is a boost to the local economy, so I imagine the building departments are under pressure by community leaders.

Megazord3 months ago

Man this is totally awesome ! If one day I have to build a small storage shed or a real house, be sure you inspired me to try this earthbag technique !

mylife12501 year ago
These instructions were easy to follow, I just can't make up my mind what to build now......a cubby house for the kids or a craft room/workshop for myself.
Macki1 year ago
Approx how many layers of plaster are needed for this finished looked?
Owen Geiger (author)  Macki1 year ago
Usually three layers -- one to fill the gaps, one to even out the walls, one finish coat. Be sure to allow ample time for each coat to dry thoroughly or moisture will get tramped and crack the upper layers.
Owen Geiger (author)  Owen Geiger1 year ago
That should say "or moisture will get trapped" ...
This is more of a concern than conventional buildings since the plaster is much thicker.
Cham4Gabi1 year ago
Good morning (SA time) Owen, I love your idea of building an eartbag home,sounds fantastic,we have a piece of land in a rural area and need to build a home within a period not exceeding 6 months,our initial plan was to build a roundhouse, which we in South Africa call a rondavel,it is cost effective and quicker to build,but we were going to use blocks as we had never heard of earhbags used to build homes,we have spoken to a few freinds and families informing them of our plans and got a negative response from them,however we are going to go ahead with our plans and build an earthbag roundhouse,I would like to know more about the bags,perhaps you could share with me where could purchase these bags,the dimensions of the bags and the quantity you used to build the roundhouse,who knows, we could be starting something here in Kwa Zulu Nata, SA. Thank you ever so much for sharing this wonderfully cheap way of building homes. We totally love your ideas.
Charmaine Slade
Owen Geiger (author)  Cham4Gabi1 year ago
Basic information like this is on our websites for free. Here are a few links to get you started:
Natural Building Blog -- see our FAQ page and use the built-in search engine
EarthbagBuilding.com
Step-by-Step Earthbag Building Instructable
akasamati1 year ago
What a great technology, thanks for sharing it in such a clear and informative way.
Do you have any tips for using this method for building outdoor retaining walls? I'd like to build a wall up to 1 metre high. Would it need reinforcing, or to be sloped back into the bank? What about the inside of the wall, would that need to be rendered so as to keep water out and protect the plastic of the bags from deteriorating? We are in a frost-free area. Thanks
Owen Geiger (author)  akasamati1 year ago
Our Natural Building Blog and other websites have thousands of pages of free information on almost topic, especially things that can be built with earthbags. Earthbags are perfect for retaining walls, because sand bags were designed to hold back the force of floodwater. Use the built-in search engines.

Here's one example: http://naturalbuildingblog.com/green-retaining-walls/

This topic is also covered in my Earthbag Building Guide. In general, you want to step the earthbags slightly toward the hillside. Make sure you include adequate drainage so water doesn't build up behind the wall. Sand or gravel in the bags works best.
I truly love the look of earth plaster, it's very rich and warm feeling. How often does this need to be patched, usually? And I was wondering, have y'all ever used decorative tile on the interior window sills? And in door surrounds? I have no idea how to get a good bond on earth plaster-the usual methods of installing tile, or something additional or different? I'm a ceramic artist, is why I ask. I thought those would be really pretty touches.

Leigh
Owen Geiger (author)  urbangleaner561 year ago
Old adobe building with earthen plaster have lasted hundreds of years. You can tour old buildings in the American Southwest. Durability depends on using the right mix, having good soil, applying it correctly, protecting from roof leaks and insects, etc.
It is easy to patch if there is a problem.

Decorative tile is great. It's an excellent choice, especially around windows and countertops and bath areas. I just posted an article the other day about accent tile on our blog. (Just basic info to introduce the concept.)
http://naturalbuildingblog.com/accent-tile/
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