When the Mississippi floods, people use earthbags to hold back the water. And when you buy a sack of oats for your horses, it might come in a polypropylene bag—the same kind that they fill with sand or soil and use to direct the flood waters. But did you know you can build permanent structures with the same bags? In fact, you can get the material they make the bags from in a big roll—it is one long continuous tube at that point! This is before they cut it into smaller pieces and sew it to make bags—and that’s often even easier to use than the bags!
This building technique, which can use a wide variety of soil types, is called Earthbag Building. You can build foundations out of it, retaining walls, square houses, round houses, amoeboid houses, arches, vaults, domes, sculpture, benches, privacy “fences.” The list goes on!
Once you cover the sun-vulnerable woven polypropylene bags in either earthen, lime, or cement stucco, you have a very durable mass wall capable of carrying heavy loads such as cob, or adobe. And you can put the bags directly in contact with the ground, but you can’t do that with any earthen materials or straw and expect them to last. Thermally, earthbag acts a lot like adobe, cob, rammed earth, or earthships (tire houses), but is easier to build.
In the late 90’s, Steve built an earthbag house in the Bahamas with Carol Escott. They had heard about it at a natural building colloquium from Kaki Hunter and Doni Kiffmeyer, who had built an earthbag dome in Moab, Utah. So Steve and Carol asked them to come teach them their tricks and help them start it off—which they did! Eventually Kaki and Doni wrote a great book on the subject, and we highly recommend it! It is called Earthbag Building: the Tools, Tricks, and Techniques. Since then, Steve and Doni have also taught earthbag building in Jamaica.
Though we love straw bales for lots of functions such as houses, studios, wine rooms, etc. (they insulate so well!), they really don’t do well in contact with the ground. Since we moved to our place in Asheville, NC (which had absolutely no flat spot!), we have done a little grading and built some nice dry-stacked stone retaining walls, but we need more! So we have been thinking about and planning out some earthbag retaining walls. Earthbag is one of the few natural building techniques that can be in contact with the ground and not suffer.
We look forward to sharing our earthbag expertise with workshop participants on May 2-3, 2015 in a very affordably-priced two-day workshop called Earthbag Construction: Basics and Beyond. We are going to use mostly tubes. We will probably only use bags for the arch demo we are going to do.
Steve and four work exchangers (who are attending the workshop for free in return for help preparing the spot) did a ton of digging the other day, as you can see from the photos! This resulted in no less than four piles of soil in our yard. It is always astounding how soil “expands” when you dig it up! Some of these piles will get used to fill the tubes, but we will fill a good percentage of them with gravel. Also, we will fill the footing trench with gravel (and a drainage pipe).
If you want to read a bit deeper into the earthbag method, check out this informative and fun article by Kaki and Doni—they are excellent writers. And good people too! And you can always subscribe to our Hug Some Mud newsletter to stay informed about our next straw bale, cob, earthen paint, lime and earthen plaster, or other workshops (just go to the Subscribe link at the top right on any page of mudstrawlove.com). Plus, we’ll be writing some more blog articles about natural building. Don’t worry, we won’t inundate you with too many emails!
More About the Instructors
One of the things Steve and I (Mollie) really love to do is pass on our knowledge, tips, techniques, and enthusiasm about natural building—straw bale, earthen paints and plasters, cob, earthbag, and more. We have been teaching for a long time (about 44 years worth between the two of us!), and doing natural building for a bit longer than that. We have learned a lot in those years, and taught a lot too—and still think we have a lot to learn. So we encourage our students/workshop participants to glean whatever is most helpful from us, and also to think for themselves and let us know how they think we could do it better. We love to see people excited and empowered by gaining the knowledge they need to make their own dreams come true in an environmentally conscious way.