loading
Picture of How to Build an Earthbag Roundhouse
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

Step 1: Earthbag Foundation

Picture of Earthbag Foundation
3rd course complete.JPG

Earthbag foundations – gravel-filled bags or stabilized bags – offer many advantages over reinforced concrete foundations and work well with many types of sustainable buildings. In particular, they are low-cost, fast and easy to build, require no cement (a major expense and cause of global climate change), and require no forms or expensive equipment. In cold climates you can use lava rock or pumice to create an insulated foundation. This one simple step can save you thousands of dollars over building with concrete, and cut your energy costs.

Typical earthbag foundations are made with poly bags (double-bagged for strength) filled with gravel. Aggregates are preferred for foundations because they will readily drain away any moisture and prevent wicking into the wall system. Some prefer to use stabilized soil in earthbag foundations, seeing it as a longer lasting solution. The jury is still out, but it appears poly bags kept out of sunlight can last hundreds of years, so gravel-filled bags should last at least a lifetime.

Simply fill the bags in place with gravel. Stitch the ends closed or fold the bag end over. Butt each bag tight against the previous bag. Tamp the bags flat after each course is complete. Add two strands of 4-point barbed wire between each course. Add courses of gravel-filled bags until you’re at least 6” above the risk of moisture damage.

Step 2: Door Thresholds and Door Bucks

Picture of Door Thresholds and Door Bucks

You’ll want durable thresholds at entry doors. I recommend concrete or stone for this purpose. In this method, finished floor height (F.F.) is the same height as the threshold. In other words, the threshold and floor will be exactly the same height. To build the threshold this way, pour a 2”-3” concrete threshold, sloped slightly for drainage, on top of the earthbags at each entry door location,. You can add concrete pigment to make it any color you want. Allow adequate time for drying (about one week, depending on the temperature), and then set the door buck on the threshold and brace securely in position.

Step 3: Stacking Soil-filled Bags

Picture of Stacking Soil-filled Bags

At this point you can continue stacking courses of bags for the remainder of the walls, but now the bags are filled with soil. (Although there are numerous alternative fill materials. See our Earthbag Building Blog for full details.) Most subsoil is suitable for earthbag construction. Subsoil is the clay/aggregate soil that’s below the topsoil. You could dig your own, but you can buy it very inexpensively and save many days of hard work. You can also buy an engineered mix called road base, which contains the ideal ratio of clay to aggregates, no mixing required.

Step 4: Measuring the Radius

Picture of Measuring the Radius

Measure the radius of each course of bags to maintain an accurate circle. Tie a piece of rope to the center pole and use it to check the radius to every bag. Always keep the rope level for accurate results.

Step 5: Tamping and Leveling

Picture of Tamping and Leveling

Tamp earthbags solid and level after each course is complete. Tamp the high points first. Then evenly tamp the entire wall several times as you continually move the tamper. This last step avoids creating low spots. And if you use the same number of buckets of soil in each bag, and are careful placing the bags, the courses are almost self-leveling. Consistency is the key. Use the same process for each bag. Remember to place two strands of 4-point barbed wire between every course.

Step 6: Metal or Wood Anchors

Picture of Metal or Wood Anchors

Add metal or wood anchors every few courses to secure door and window bucks to the earthbags. Most people use wood anchors. But in areas with termites, it’s best to use anchors made of galvanized sheet metal. They’re inexpensive, strong, easy to make from scrap metal, resistant to decay and, because they’re thin, they don’t take up space between bags like wood anchors do. In most cases, sheet metal anchors are preferred over wood anchors. Simply nail into the earthbags with galvanized nails and screw into the backside of the bucks.

Step 7: Anchors for Electrical Boxes

Picture of Anchors for Electrical Boxes

Most earthbag builders use some type of improvised wood or plywood anchor to attach electrical boxes. I’ve found the simplest solution to be 3” wood poles. A rot resistant variety is best. Embed the poles between courses wherever you want an outlet or switch. If you forget or want to add extra boxes, sharpen the end of the pole and drive it into the wall with a small sledgehammer before the soil gets too hard. Use an electrical box as a depth gauge. You want the front of the box to protrude about 1-1/4” beyond the earthbags to match the plaster. After the walls are built, screw boxes to the stakes with two screws and staple or nail the wiring in the recesses between bags. Complete all the rough electrical work before plastering.

Step 8: Window Bucks

Picture of Window Bucks

Set window bucks on the wall when you reach windowsill height. You can pre-build the bucks while your threshold is drying. Use standard carpentry techniques to brace the bucks square, and to keep the buck plumb and level. We use double 2x4 bucks instead of wide lumber, and we use poles for braces instead of milled lumber to cut costs. It’s often a good idea to pound ½” rebar down through the bags on either side of door and window openings if you have lots of openings like we do.

Step 9: Bond Beam

Picture of Bond Beam

It’s easiest to build a bond beam immediately above windows and doors so you don’t have to build lintels. This method saves hundreds of dollars and one whole step. Reinforced concrete or wood bond beams are both acceptable. You’ll want to read up on these building steps since the subject is too involved to summarize in a few sentences. We used concrete due to the prevalence of termites in our area. We used two layers of ¼” plywood as forms, ½”rebar pins pounded in the tops of walls, and ½” horizontal rebar. Pour the concrete nonstop so you don’t have any joints. Embed hurricane ties in the concrete for securing roof poles. Allow to dry several days before stripping the forms and building the roof. Any voids in the concrete can be patched when you plaster.

Step 10: Build the Roof

Picture of Build the Roof

Build the roof after the bond beam is finished. Any type of roof is possible, and space doesn’t allow a lengthy discussion. We used a metal compression ring with radiating wood poles covered in thatch. Create large roof overhangs of approximately 30”-36” to protect walls from moisture damage. The exact size will depend on your climate.

The roundhouse has a super strong feeling due to the concrete bond beam, thick walls, sturdy poles and round shape. You could probably have a dozen workers on the roof with no visible effect. The roof frame went together almost like clockwork. The compression ring worked perfectly. The roof was all bolted together in about 4 hours, in part because the poles were precut and prefinished in advance.

Thatching is usually very slow and laborious, but we thatched our roundhouse in just one day and for only $100 using pre-made thatch panels. That's why I love thatch panels - they're very inexpensive and all the tedious work has already been done. And they work great on round (conical) and organic shaped roofs because they're flexible. Just bend them into position and nail in place. We installed the panels using 8" spacing. Plan on rethatching every 3-5 years or so, depending on the quality of your thatch. Some thatch will last 10 years or even longer.

In cold climates you’ll want a thick roof with lots of insulation. This can be achieved with trusses or TJIs (engineered truss joists). Wide dimension lumber could also be used, however, this requires cutting old growth forest.

Step 11: Install Doors and Windows

Picture of Install Doors and Windows

Use standard carpentry techniques to install doors and windows. This boils down to simply screwing the door and window frames to the bucks so they are plumb and level. Add shims as necessary. Remove the doors after they are fitted to prevent damage. Mask off windows with plastic to reduce cleanup later.

Step 12: Cement Plaster on Exterior Walls

Picture of Cement Plaster on Exterior Walls

Here's a brief summary of the cement plastering process we used on the exterior of our earthbag roundhouse:
Step 1: Put cement between the bags in the recesses.
Step 2: Add thin coat of cement over bags.
Step 3: Add more cement.
Step 4: Add more cement.
Step 5: Trowel the plaster smooth and use a sponge float to smooth out the finish.

As you can see, the process is quite simple, although labor intensive. It boils down to adding a little plaster at a time. Leave each coat rough so the next coat will better adhere. No plaster mesh is needed - the plaster sticks to the earthbags, no problem. Resist the temptation to overwork the plaster or you’ll lose adhesion to the bags. The total process took about five days of work for two workers spread out over a little more than week. A third worker helped the last day. Use best practices in your area. Always prevent plaster from freezing. Keep plaster moist and allow to dry slowly for best results.


Step 13: Earthen Plaster on Interior Walls

Picture of Earthen Plaster on Interior Walls
curved int window.JPG

Earthen plaster is lowest cost, easiest type of plaster to work with. Many people find earthen plaster very enjoyable work. They’re often pleasantly surprised at how incredibly simple it is. After all, the main process is basically smearing mud on the walls. Follow one of the free recipes on the Internet. Experiment with small patches to help determine the optimum mix for your materials. Add more sand or less water if the plaster cracks. Add more clay if the plaster doesn’t stick to the walls.

The first step is to fill the recesses between bags and apply plaster around doors and windows. Plaster mesh is recommended around all windows and doors to help prevent cracking. You can apply earthen plaster with your hands or with a hawk and trowel. Allow each coat to thoroughly dry before adding additional coats. Leave each coat rough so the next one will more readily bond. Add more coats of plaster until your walls are finished. Smooth the final coat until you’re satisfied with the results.

2nd photo: Here you can see the natural beauty of earthen plaster that's been sculpted to gracefully curve around window and door openings. This not only looks good, but also lets in more light and improves the view. I want to emphasize how this simple concept totally transformed our roundhouse from a bunch of bags into a thing of beauty. Click here for more details about rounded corners. 

Step 14: Finishing Details

Picture of Finishing Details
At this point you can finish your electrical and install plumbing fixtures. You can also install doors, trim, shelving and cabinets, and then stain and varnish any woodwork, and paint your home. But plastered earthbag walls don’t require painting or trim. Many builders plaster right up to windows, doors and floors. This is another major time and cost saving advantage of building with bags.

Step 15: Interior View

Picture of Interior View

Finishing details turn a house into a home. It's what people really notice. If you want a really nice home, be sure to plan accordingly and give this some extra thought. Finishing work does require extra time and effort, but the results are definitely worthwhile.

Interior view showing natural color of earthen plaster, recycled windows and yellow concrete floor. For the floor, we troweled natural iron oxide pigment on the surface before the concrete set up. The pigment is sprinkled by hand and troweled into the top ¼" as the concrete sets up. A little more color was added later during final troweling to even out the color. We were careful to moisten the sand and gravel under the floor to slow drying and prevent cracking.

Step 16: Exterior View

Picture of Exterior View
finished bench.JPG

Step 17: Conclusion

Picture of Conclusion

It boggles the mind how flimsy stick-built houses meet code and yet some people have doubts about earthbag building. (And even more hilarious is how trailer houses are somehow considered safe and adequate.) Let's briefly compare stick frame and earthbag houses: A strong person could readily kick their way through pressed board siding and sheetrock in about one or two minutes. The same person would probably be struggling an hour later trying to penetrate an earthbag wall, even with a sledge hammer, pick, shovel and crow bar.

What type of house would you rather live in? One that is thick, quiet, energy efficient, non-flammable, non-toxic and dirt cheap? Or one made of sticks and toxic materials that burn like crazy, offgass toxic fumes, leak energy and cost a small fortune. Earthbag is inexpensive enough that you don’t need a mortgage. Instead of spending 30 years paying off a mortgage, build super inexpensively and have far more time to spend with your family and friends, and help build community. This also lessens the influence of big banks, which are wrecking society with their greed.

Remember, over 70% of Americans can’t afford a contractor built home built to code, and that was before the current housing crisis. And since earthbag building is far faster and less labor intensive than adobe, cob and rammed earth, it’s one of the best of all possible sustainable housing options.

And as a final word, I want to say anyone can do this. It’s as basic as filling and tamping bags of dirt and covering with plaster. Just take some time to do the necessary background research and maybe start out by building a small storage shed to refine your techniques. Almost everything you need to know is free on our websites.

Step 18: Final Earthbag Roundhouse Video

Picture of Final Earthbag Roundhouse Video
roundhouse2.JPG

1-40 of 227Next »
thalesvga4 months ago

Hello!

Can I fasten shelves and things like it? How does the walls behave with screws?

Owen Geiger (author)  thalesvga4 months ago
My earthbag book covers this topic Attaching Things to Earthbag Walls.

Add wood blocking between the bags as you build. That way you can screw cabinets, shelves, etc.into the blocking. Same with electrical. This requires a bit of pre-planning to figure out where you want to put things.

Lightweight things can be supported with big nails or 1/4" rebar pins drive in at a downward angle.
onijohnson6 months ago

Thank you so much for this tutorial. It was so easy to follow. and now im here dreaming about building my dream home in joshua tree.....

ford.crews6 months ago

I always wanted to make a house like this, but use used tires packed with dirt for the outside walls, get rid of the old tires, and nothing can beet 2 feet of earth as far as insulation goes.

Owen Geiger (author)  ford.crews6 months ago
Earthbag is quite similar to rammed earth (an ancient building method). That's the same rammed earth in the tires. Except here we're using bags instead of tires. Making earthbags is so much faster and easier there's no comparison. One rammed tire takes around 45 - 60 minutes from what I've read. You can do one earthbag in five minutes. Using tubes is even faster. Maybe twice as fast. Plus, there's no concern over offgasing. The wall surface is flatter and uses far less plaster than filling gaps between tires.
bahayaliwan7 months ago

what is the best material to use as a divider to make a bathroom in a round earth house?
Owen Geiger (author)  bahayaliwan7 months ago
The "best" solution depends on what materials are locally available, durable, practical and affordable, and on your skills. We used low fired clay brick because it's waterproof. Most people use wood framed walls with the pipes in the walls. Our pipes are on the surface (local custom) so they're easy to maintain.
bahayaliwan7 months ago
Hi Owen,
Im planning to build an earth bag round house.
can you send me a floor plan where to place sink and bathroom.
Owen Geiger (author)  bahayaliwan7 months ago

The Roundhouse Studio plans are available at Dream Green Homes.com.

http://dreamgreenhomes.com/materials/earth/earthba...

But this plan is so simple and this Instructable explains everything so you may not need the plans. In general though, the sink and bath are usually adjacent to each other to simplify plumbing.



Beautifully earth bag house look nice cost is also less. This roundhouse
demonstrates how anyone can build their own home even on a very tight budget.
For those who are not living that type of home, take
care in weather changing so that could live safely specially for roof it is
worst time. Keep EPDM with you as precaution. For more to know please visit

http://www.epdmcoatings.com/





Owen Geiger (author)  liquidroofrvrepair8 months ago

EPDM is very expensive. I would only use it on a living roof if the budget allowed. Metal roofs are much less expensive.

Do you have any resources or advice for building a double storey roundhouse? I am beginning to build in the New a Year (2015) and am starting to plan the details...thanks!

Owen Geiger (author)  Edwardmartinhill9 months ago

I just emailed you. Use lightweight building materials on upper stories because soil is very heavy.

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)  urbangleaner5610 months ago

Up to you. Cement plaster is the standard and likely the most resistant to flooding.

Water is the #1 enemy of buildings, so raise your building site above flood stage or building on high ground. Use gravel bags on lower courses. Plastic sheeting under the floor to prevent wicking. Slope the ground away from the building in all directions.

Owen Geiger (author)  urbangleaner5611 months ago

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

Owen Geiger (author)  urbangleaner562 years 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.
jim_skofield10 months ago

Hi Owen, loved your article. I live in Michigan and we tend to have crazy winters here. I'm wondering if a project like this would be feasible in our high humidity environment.

Owen Geiger (author)  jim_skofield10 months ago

Yes, but you need to modify the design for your climate. This one is for the tropics. You want fewer windows, insulating south facing windows, roof insulation, durable roofing, lots of wall insulation, floor insulation, heating system, insulated door, etc. Read up on climate appropriate design or climate responsive design.

http://collections.infocollections.org/ukedu/en/d/Jsk02ce/3.4.html

Awesome! thank you very much. you have been incredibly helpful

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)  urbangleaner5611 months 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)  urbangleaner562 years ago
Yes. Use typical plastic sheeting, also called 6 mil poly.
J-Ri1 year 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-Ri11 months ago

No problem.

Owen Geiger (author)  J-Ri11 months 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.

kruklanki2 years 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)  kruklanki11 months ago

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

Owen Geiger (author)  kruklanki2 years ago
You can email me at:
naturalhouses [at] gmail dot com
kruklanki2 years 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)  kruklanki11 months 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)  kruklanki2 years 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.
wwylde2 years 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)  wwylde11 months 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.

bandara1 year ago
Very interesting and very beautiful low cost house.
Owen Geiger (author)  bandara11 months ago

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

njc1219831 year 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)  njc12198311 months ago

Thank you.

HydePoison1 year 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)  HydePoison11 months 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.

1-40 of 227Next »