Step 13: Earthen Plaster on Interior Walls

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. 

<p>Beautiful building; I like the round design, but I wonder, how would these walls hold up if stacked vertically, in the more traditional manner? That bond beam looks like it can support basically any kind of roofing type. I'm thinking a man who wanted to own an (eventually) sprawling home could just stack more bags and plaster them to add on to any house. <br><br>Maybe I'll start with a shed...</p>
<p>Yes, start with a shed to develop your skills. You can use any roof method you want. You can add on in the future if you plan for it. I don't understand your first question. The walls are stacked vertically in this roundhouse.</p>
<p>Hello!</p><p>Can I fasten shelves and things like it? How does the walls behave with screws?<br></p>
My earthbag book covers this topic Attaching Things to Earthbag Walls.<br><br>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.<br><br>Lightweight things can be supported with big nails or 1/4&quot; rebar pins drive in at a downward angle.
<p>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.....</p>
<p>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. </p>
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.
<br>what is the best material to use as a divider to make a bathroom in a round earth house?<br>
The &quot;best&quot; 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.
Hi Owen,<br>Im planning to build an earth bag round house.<br>can you send me a floor plan where to place sink and bathroom.<br>
<p>The Roundhouse Studio plans are available at Dream Green Homes.com.</p><p><a href="http://dreamgreenhomes.com/materials/earth/earthbags.htm" rel="nofollow">http://dreamgreenhomes.com/materials/earth/earthba...</a></p><p>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.</p>
<br> <br> Beautifully earth bag house look nice cost is also less. This roundhouse <br> demonstrates how anyone can build their own home even on a very tight budget. <br> For those who are not living that type of home, take <br> care in weather changing so that could live safely specially for roof it is <br> worst time. Keep EPDM with you as precaution. For more to know please visit <br> <br> http://www.epdmcoatings.com/ <br> <br> <br> <br> <br> <br>
<p>EPDM is very expensive. I would only use it on a living roof if the budget allowed. Metal roofs are much less expensive.</p>
<p>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!</p>
<p>I just emailed you. Use lightweight building materials on upper stories because soil is very heavy.</p>
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. <br> <br>Leigh
<p>Up to you. Cement plaster is the standard and likely the most resistant to flooding.</p><p>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.</p>
<p>You can use cement or lime plaster. Some mix the two. Recipes are free on the Internet.</p>
Lime plaster is great. Read up on the details and follow the instructions. <br> <br>Raise the building site above flood stage. We did this by dumping truckloads of road base in 6&quot; layers and driving a truck back and forth over the top in opposite directions.
<p>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. </p>
<p>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. </p><p>http://collections.infocollections.org/ukedu/en/d/Jsk02ce/3.4.html</p>
<p>Awesome! thank you very much. you have been incredibly helpful</p>
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. <br> <br>Leigh
<p>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.</p>
Yes. Use typical plastic sheeting, also called 6 mil poly.
This is absolutely amazing! I think I'm going to give it a try. <br> <br>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. <br> <br>Thank you so much for the instructable and a reply if you have time!
<p>No problem.</p>
<p>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.</p>
Hello Owen <br>Your building methods are astoundingly simple and effective &ndash; 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? <br> <br>Thanks <br>Peter McLaren. Udon Thani <br>
<p>Yes, that's the price in Thailand. I live in Isaan.</p>
You can email me at:<br>naturalhouses [at] gmail dot com
Hi Owen <br>I find your ideas very inspiring <br>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&rsquo;t think of any cheap material to build it with. I don&rsquo;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. <br>I can get bamboo for next to nothing and cover the roof with it which should look good from the inside but I&rsquo;m at a loss then to know how to waterproof it on the outside. I don&rsquo;t want to have to screw tiles to the bamboo if I can help it. <br>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&hellip;&hellip;.in the middle of the two? <br>
<p>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.</p><p>Lower walls for earth berming: You could use regular bags all the way if the berm is only 24&quot; high.</p>
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.<br><br>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.
Any success with structure shapes besides &quot;round&quot;? Can you free form the design in a fashion similar to the &quot;super adobe&quot; style or . . . ? <br>Also: what kind of size/span limitations have you encountered with this method? <br>
<p>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.</p>
Very interesting and very beautiful low cost house.
<p>Thanks. We added new MCR tile roofing and it looks even better.</p>
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 &quot;ible&quot; when I need to add on to my current domicile.
<p>Thank you.</p>
<p>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 :/</p>
<p>99% is the same as any house. Check out the simplest books you can find from the library. I like the little &quot;pocket guides&quot; 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.</p>
<p>From start to finish how long did it take and how many. </p>
<p>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.</p>
<p>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.</p>
<p>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.</p>
<p>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.</p>
<p>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.</p>
<p>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 !</p>
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.

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Bio: Owen Geiger is the former director of Builders Without Borders, a Mother Earth News Green Home Adviser, The Last Straw Journal Correspondent and the director ... More »
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