There’s great, untapped potential for superinsulated earthbag buildings in cold climates. Here’s a way to combine the best features of earthbags and yurts. The basic idea is to combine earthbag walls filled with lightweight insulation such as scoria (lava rock), with a traditional yurt roof frame that’s insulated with perlite or vermiculite.
Yurts (ghers) have been used in Mongolia and other areas for centuries. Traditional yurts are well suited for cold, windy places, in part because the wind just blows around them. They can, however, be made even more comfortable with extra insulation in earthbags.
Scoria is perfect for superinsulated earthbag walls: low cost, all natural, rot proof, fireproof, doesn’t attract pests, lightweight and easy to work with. Scoria is great for building walls since the aggregates tend to lock together and form stable walls. Tie courses together with twine for best results, and then cover walls with canvas.
Yurt roof frames are readily available through numerous suppliers, and fast and easy to assemble. The steel tension cable is strong yet light. They are very resource efficient, using minimal wood, but often lack adequate insulation. I recommend tying bags of lightweight insulation to the bottom of the frame. Perlite and vermiculite would be excellent choices for ceiling insulation since they’re very lightweight.
This design is portable, just like traditional yurts. The entire structure can be disassembled and transported if necessary. This would be a dream structure for places like Minnesota, Canada, Alaska, Siberia and Mongolia because it would be super comfortable, inexpensive, portable, wind resistant, owner built and could be built in many sizes. Add a skylight, rocket stove, small solar panel and composting toilet and then you can laugh at the wind howling by.
Note: you can use recycled bags if available (often farmers have them). You can also order tubes from poly bag suppliers. They make custom sizes. Tubes are faster to fill since you don’t have to stop and tie the ends as often. A 12″ tube (measured when empty) that provides 10″ of insulation when filled would be ideal for many cold climates. Simply tie the tubes to the yurt frame with twine. Use whatever insulation is most practical in your area.
This is the first time I’ve encountered scoria and I’m curious as to how much this would cost me? I’m about to build a yurt with https://www.simpleterra.com/yurt-kits/ and they use a 3-layer insulation.
Scoria varies quite a bit in cost from region to region. In areas where such volcanic stone is prevalent (mostly the west coast in the US) it can be fairly inexpensive, but in other places it can be quite costly or even unavailable. I suggest checking at landscape supply outlets for this.
Now I’ve got some decisions to make. I’ve been looking at yurt kits on simpleterra.com to put on my property, they have some cool looking yurts. But this idea really intrigues me. I’m curious what the price is for making a yurt in this style?
Yurts have intrigued us for awhile now. We got a quote for a cabin and it was around $250,000, while the yurt kit that we’ve been looking at is $29.256. I priced out material for building a platform and foundation and I think the total cost will be around $40,000.
Well, if you started with a yurt kit, as suggested in this blog post, the cost of adding earthbag insulation would add the cost of the bag material and whatever insulation material you could source. Scoria is good, but it is not available everywhere. Other options might be rice hulls, perlite, vermiculite, pumice, or even shredded styrofoam. None of this should cost very much.
Another option might be to simply build and insulated earthbag round house and create a yurt-style roof for it. That might be the cheapest solution of all.
It seems like a yurt structure with a heavier earthbag filling and a substantial surrounding berm might withstand tornadoes!
You would still be at risk of flying tree branches and other debris coming through the roof.
Please send me info, brochure, catalog, e-mails on upcoming earthbag yurt building workshops in Dec’10, and any workshops upcoming in 2011. Thank you,
There are no earthbag yurt workshops. What I wrote about is just a simple idea that may be helpful to others.
What a combination! Thanks for the article.
unfortunately yurt companys won’t sell the roof system seperately. too bad.
It sure seems like they would sell replacement roofs. What do they do if someone’s roof is damaged?
If you have to buy a whole yurt, the canvas will protect the earthbag walls.
Buy a larger sized yurt to offset the space taken up by thick walls.
I did a Google search for yurt roof frames with no luck. Will you point me in the right direction, please? Also, have you abandoned the barbed wire on these bags? How frequently do you tie the horizontal rows with twine? 2 rows at a time?
Thanks.
Jack
Every yurt company sells roofs for their yurts. So buy a yurt and the roof comes with it. The canvas sides will protect the bags.
Hello,
Just wanted to thank you for inspiring so many people like you have inspired me. I have tried earthbag building for the first time in my back garden and built a bench (link below). Although it is a very modest construction, I am really pleased with the result and hope to continue using this technique in the future :)
http://theroofabovemyhead.blogspot.com/2009/09/earthbag-building-in-oxford-part2.html
Best wishes,
Célia
So I’m hoping to build an earthbag style structure in South Eastern Oregon. I was wondering if you could refer me to someone in the N. California, S. Oregon area who would be willing to accept me as a student or apprentice, or who would just be able to shed light on the subject, as I have only heard of this building over the last few months. I would take one of the courses but I’m kinda broke!
thanks
Luke
There’s lots of natural building going on in your area. Just keep looking.
However, earthbag building is not widespread yet. I suggest reading and re-reading everything on our sites and then building yourself a small prototype structure — maybe a storage building, etc. — to learn the basics.