There are two ways to build earthbag structures. You can either create a round self-buttressing structure using bags tethered with barbed wire and no wood at all (usually cheaper and easier), or you can make a post-and-beam structure and fill in the walls. Oftentimes the reason people make post-and-beam structures is for square earthbag houses, or to pass building regulations. But here’s something a little different:
Kristen Krash of the inspiring regenerative project Sueno de Vida in Ecuador shared a fabulous explanation with us in The Mud Home Facebook Group of how she made her unusual earthbag and bamboo kitchen. I say unusual because this is the first time I’ve personally seen earthbag on a bamboo post-and-beam structure, so of course I had some questions.
How did you make the bamboo post-and-beam frame?
“Ah, the bamboo is actually anchored onto columns that go 50cm into the ground,” explained Kristen.
Kristen and Juan buried limecrete columns into the rubble trench below. The columns were made using a gravel, lime, and cement mixture poured into wooden moulds, with long rebar set into the mixture while it was still wet. Kristen reuses everything, so once the mixture was set they stripped off the wood from the moulds, cleaned and sanded it, and used it to make shelves.
“The bamboo columns that hold the vigas that support the roof (you can see the "fish mouth"-shaped cuts in the bamboo that hold it together like puzzle pieces) are anchored onto the rebar. So the roof is actually directly connected to the rubble trench through the bamboo/rebar combo, which integrates the structure and gives it a lot of flexibility in an earthquake. It shakes and shimmies but doesn't fall,” Kristen told us.
How did they anchor the earthbags to the bamboo?
“The earthbags in our case are not continuous. They are simply sections of infill. The space between each bamboo/column is about two metres. That's five one-hundred-pound sacks in each row. Five rows high, that's a 2,500-lb wall. Properly staggered like bricks, decently plumb, and connected with barbed wire, they aren't going anywhere,” Kristen explains.
But the way they kept some kind of integrity in the structure was with the barbed wire. That is continuous. They laid it in between the bags and just kept going with it around the outside of the columns to make a continuous circle.
“We've had four mid-range earthquakes and the bags also shimmy a bit but they don't slide or move,” Kristen says. “Of course I wouldn't recommend this method if you were building up really high with your walls or expected them to bear the weight of a roof. But we knew our walls would only extend up about 1.5 m and the bamboo/column combo would hold the roof.”
What about the plaster?
Kristen plastered over the columns on both the interior and exterior to cover the wire and make it all look smooth, as well as so to prevent critters from taking up residence in the crevice between the bag and column. She used a plaster mix with 2 parts sand, 1 part clay, ¾ of a part lime, and plenty of fibres.
This is such a funky little kitchen, and Juan and Kristen build this stuff on an insanely low budget, off-grid, in the middle of nowhere with no megastores or Amazon deliveries. It’s hardcore.
One of my favourite features is the diamond windows and the mosquito nets. If you’re in a mozzie-filled area, there really is no better way to protect yourself than a well-screened room. As Chris in the group asked, “where did you get all that insect screen?” In Turkey, we could get it from a normal fabric shop. They had massive rolls of the stuff and the tailor would make mozzie nets to order so you could make them huge.
But in Ecuador? “We got them in nurseries. It’s what they use to shade more delicate plants. It’s called saran,” Kristen said.
Juan and Kristen have planted thousands of trees now and are regenerating their little space. If you’d like to learn more about their project have a look at their website: https://www.suenodevida.org/
You can also support them on Patreon if you’d like to do your bit for the forests of South America. https://www.patreon.com/suenodevida
Starting Your Own Project?
The Mud Home’s small, private, and very supportive Facebook group is a safe space for new mud builders and off-gridders. It’s also the most inexpensive way to get assistance from me. It’s filling up, though. The number of members will be capped at 100 so I can give everyone the proper help they need. So if you want to be part of it, don't leave it too long.
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