What is Earthbag Building (and Why on Earth Should I Give a Damn)?
I’ve been a proponent of earthbag building for well over a decade now. When I tell people what I teach, I’d say that at least 95% of folks haven’t heard of it. The premise is simple: put dirt (a mix of sand and clay) in sandbags and build walls with it. We built our first earthbag house in 2009 and I have been an avid spreader of the dirtbag gospel ever since.
Advantages of Building With Earthbags
We live in a world full of dangers. As I write this blog post, wildfires are claiming entire towns in California, and in the area where I live, we are experiencing heavy rains from a former hurricane that ravaged the Gulf Coast. Earthbag houses are strong and the walls are fireproof. I’m also confident that, with proper planning, a person could build an earthbag house that could withstand a category 5 hurricane. Sandbags are known to stop both bullets and floodwaters. Earthbags can also be safely used in applications where they’ll be subject to lots of moisture. We built a pool using them and they are ideal for such things as underground houses, root cellars, and cisterns. Neither the bag nor the fill material are conducive to mold growth–another common and dangerous indoor air pollutant.
The EPA released a finding that, because of toxic, off-gassing building materials, indoor air pollution is usually several times worse than what we experience outside. In contrast, earthbags are non-toxic and don’t off-gas.
Another big advantage of earthbag and other earthen building methods is that the material you’ll be using is already right under your feet! No need to spend thousands and thousands of dollars on wood, vinyl siding, insulation, and the like. Since the dirt comes directly from your site or nearby, there is very little embodied energy compared to it takes to create and transport conventional materials.
Disadvantages of Earthbag Building
Buildings should always be site specific. No building method is perfect for every application. Earthbags are no exception.
In some remote places, it may be hard to get earthbags or they may be cost prohibitive. In this case wood, cob, stone, bamboo, or another indigenous material would likely be a better choice.
Like most earthen buildings, earthbag structures have a lot of thermal mass but little insulative value. This makes them ideal for climates with warm days and cool nights where they can benefit from the “thermal flywheel” effect, but an uninsulated earthbag structure in a consistently cold climate would take a lot of effort and energy to keep warm. Earthbag buildings can be insulated but that can be a bit of a challenge in itself. In a very cold climate, I think I would lean more towards a building method with a lot of inherent insulation, like straw-bale.
Earthbag building may take more work and be slower than something like stick building but the payoff is worth it in my opinion–you end up with walls that are a foot thick, fireproof, and just-about-everything-resistant.
I did a lot of research before I built my first earthbag house. I recommend doing your own research as well. When I discovered it, I knew it sounded like the right fit. After trying it, I decided it was right for me. In the future I look forward to experimenting with more natural and green building styles but for now, I find that earthbag building is my favorite.
Soon we will be releasing our online earthbag tiny house course that I’ve been working on over a year. It has several hours of professionally-filmed footage taken from our 2019 tiny house build. In it, I share our latest and most up-to-date building methods. If you’re interested, I hope you can join us online or at an in-person earthbag building workshop, such as our one in Marshall, NC next year. Thanks for reading!
http://www.naturalbuildingblog.com/ – Kelly Hart and Owen Geiger’s (RIP) blog. Has a lot of information on many types of natural building.