Instructables

How to Build an Earthbag Roundhouse

Featured
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.

 
Remove these adsRemove these ads by Signing Up
HydePoison16 hours 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 :/

njc1219832 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.
bandara4 months ago
Very interesting and very beautiful low cost house.
J-Ri5 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!
mylife12508 months 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.
wwylde9 months 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?
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)  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.
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)  kruklanki1 year ago
You can email me at:
naturalhouses [at] gmail dot com
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.
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)  urbangleaner561 year ago
Yes. Use typical plastic sheeting, also called 6 mil poly.
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/
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)  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.
sunderani3 years ago
I currently build houses out of cement blocks in the Dominican republic. I am thinking of switching to this method it looks much more economic. How much harder is it to do than laying blocks? How long would the structure last? Would it be strong enough to survive a hurricane?
Owen Geiger (author)  sunderani1 year ago
Block laying requires some masonry skills. Earthbag building is simpler, but also takes some basic know how. Read the Step-by-Step Earthbag Building Instructable for the details.

It's also less expensive than concrete block and super strong. I suggest building roundhouses in rainy, hurricane prone areas. Domes would also resist the wind, but they're harder to protect against leaks.

Earthbag is very similar to rammed earth. Instead of building expensive wooden forms, the bags work as a form to hold the shape. Google ancient rammed earth and you'll learn how some of these structures have lasted hundreds and sometimes thousands of years.
Im From the dominican republic also, and i have already built a room from stabilized earth and part cement and sand which will have a earthroof. it is work intensive But for someone who have no knowledge in putting blocks its easy for him to lay earthbags and fix hit problem without having to break it with a sledgehammer .i am glad i started small and now im planning on to finish the next part that is attached to the room which is really the house.
neillcin zapone2 years ago
I'd love to see how your project has developed. Any photos? I'm in the DR, too, and am planning to host a free earthbag building seminar near Las Galeras next spring. Maybe you will come?
Nice i dont know much where that is placed but i like the idea & im building a small bathroom inside structure and start plastering it this Wednesday then after that im planning on pouring a cement roof since the wood to support 2 feet of dirt tamped is more expensive. i dont believe it will look as beautiful as these cob home with the natural feel it much like a earthbag root celler or survival shelter . which is my idea btw im from Santiago Rodiquez . Owen what whats your opinion on this behalf ?
Owen Geiger (author)  zapone2 years ago
Yeah, start small. Your skill and speed will develop with time.
hello sunderani

i am also in the dominican republic, and would like to know if you actually went forward with your idea of building with earthen bags
If you are still here in the DR, perhaps you'd like to attend a free seminar on earthbag construction which I'm planning to host next spring. Near Las Galeras.
please send the coordinates in order to register to your seminar !
I'm not sure yet exactly when it will be but it will be on my property in Manuel Chiquito. Manuel Chiquito is where you would turn off the Samana to Las Galeras Road to go to Playa Rincon. Come visit any time...Just ask the neighbors where I live.
I am just getting started with earthbag building in the DR. It has to be less expensive than building with blocks. I am planning to host a free seminar near Las Galeras next spring.
Owen Geiger (author)  sunderani3 years ago
It's simpler than laying blocks, which require training in masonry. We provide everything on our websites to show you how to do it for free. My new book will be available in about 3 weeks if you think you want additional info.

There's no limit to the lifespan if you maintain the building. Compressed earth structures can last thousands of years. You can make them earthquake and hurricane resistant if you build correctly (roof tie-downs, plaster mesh, etc.).
Brilliant. Beautiful. Solid.
Nice commentary in your summary too.
Where is this located?
I'm guessing it's either
a) rural
b) NOT in the U.S. (obviously, not being a drywall/stick home this is unacceptable according to code)
c) both
Code doesn't require drywall/stick home construction. It's just the cheaper in some ways, and most common. Houses in the US are built from cinder blocks, poured concrete, and solid log construction. I'm sure you would have to educate the planning department, and would have some resistance, as it's not common.
Owen Geiger (author)  integrator3 years ago
That's right. People tend to do things like everybody else -- herd mentality. But yes, building codes accept Alternative Materials. (It's actually in the code.) It just takes more knowledge and perseverance to use unconventional methods. In urban areas it's probably best to hire an architect or engineer who specializes in these things to guide you through the process. Otherwise, you might experience lengthy, frustrating delays. It's far easier to gain approval in rural areas.
Ah, so it's not the codes that are rigid, it's the enforcers/interpreters.
I kindly remind you that there is no uniformity to housing codes because they are under the jurisdiction of municipalities (not state or federal) but some loosely base it on the IBC (International Building Code) which is starting to catch on.
You are also correct that Interpretation or misinterpretation of the code official can also be a determinant factor whether your project will be approved or not.

Regarding new technology in the building industry, the rigidity comes from building officials not wanting to stick their neck outs without statistic proof that the technology is safe and tested by a governing body such as ASTM or UL. The bottom line is that building officials do not want the legal responsibility of a potentially catastrophic accident if the product/technology has not gone through rigorous testing.

There is a way by which you "MAY" get this kind of project (Earthbag system) approved in your city. It requires a full set of plans and hiring a licensed structural engineer, preferably someone licensed in your state and has some working experience and knowledge with calculating loads for homes and Earthbags a plus, it would not hurt if this engineer knows the building official in your city to do the load and material calculation for your house design. The official maybe convinced enough to allow you to build with Earthbag system if your engineer will stamp it..
I believe that it is mandatory for new houses in Boulder or Aspen, Colorado to have a civil/structural engineer's stamp for a building permit. Engineers there will surely know how to do the calcs for this type of houses
Pro

Get More Out of Instructables

Already have an Account?

close

PDF Downloads
As a Pro member, you will gain access to download any Instructable in the PDF format. You also have the ability to customize your PDF download.

Upgrade to Pro today!