Intro
Intro: 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 Build...
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Step 1: Earthbag Foundation
Earthbag foundations – gravel-filled bags or stabilized bags – offer many advantages over reinforced concrete foundations and work well with many typ...
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Step 2: 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 sa...
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Step 3: 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 nu...
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Step 4: 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 ev...
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Step 5: 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 conti...
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Step 6: 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 termite...
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Step 7: 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 ...
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Step 8: 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 tec...
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Step 9: 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 o...
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Step 10: 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 compressi...
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Step 11: 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 ar...
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Step 12: 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 th...
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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 ...
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Step 14: 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 an...
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Step 15: 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...
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Step 16: Exterior View
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Step 17: 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 ...
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Step 18: Final Earthbag Roundhouse Video
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.
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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Step 1: Earthbag Foundation
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.
Thanks so much for these instructions, you share and I teach so that others can share and teach and we can all live.
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