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How to Build an Earthbag Roundhouse

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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 compression ring with radiating wood poles covered in thatch. Create large roof overhangs of approximately 30”-36” to protect walls from moisture damage. The exact size will depend on your climate.

The roundhouse has a super strong feeling due to the concrete bond beam, thick walls, sturdy poles and round shape. You could probably have a dozen workers on the roof with no visible effect. The roof frame went together almost like clockwork. The compression ring worked perfectly. The roof was all bolted together in about 4 hours, in part because the poles were precut and prefinished in advance.

Thatching is usually very slow and laborious, but we thatched our roundhouse in just one day and for only $100 using pre-made thatch panels. That's why I love thatch panels - they're very inexpensive and all the tedious work has already been done. And they work great on round (conical) and organic shaped roofs because they're flexible. Just bend them into position and nail in place. We installed the panels using 8" spacing. Plan on rethatching every 3-5 years or so, depending on the quality of your thatch. Some thatch will last 10 years or even longer.

In cold climates you’ll want a thick roof with lots of insulation. This can be achieved with trusses or TJIs (engineered truss joists). Wide dimension lumber could also be used, however, this requires cutting old growth forest.

 
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mooy3 years ago
Im a big fan of the earthbag way of building. It seems like a good go way to get in to earth building.

One thing I have been wondering about with this thatch panel roof.
Does the roof have openings between the roof and wall? I would suspect that birds would like to get in the house when Im not home :-)
Are the thatches really that bendable? They have to be bent REALLY much at the top.

I would like to see more of the compression ring. How it work and things.

I will probably be down to Kranuan, Thailand this summer and hope to come by and say hi. I would probably need to get som hands on experience of plastering before trying my first house.
Owen Geiger (author)  mooy3 years ago
Yes, there are gaps at the top of the wall for ventilation. We were going to screen these to keep out birds and insects, but never did and no problems so far.

The thatch is attached to a strip of bamboo that bends up to a point. Bend it too far and it breaks, but that's okay. It's all nailed in place and doesn't show. The compression rings works great. Highly recommended if you can find a shop that can make it.

Stop by any time. Email me before you come. My email is listed on our websites.

There's an earthbag workshop April 1. You're welcome to attend.
http://earthbagplans.wordpress.com/workshops/
vincent75203 years ago
How thatch panels can be inexpensive where you are ?
Here (France) a thatched roof , a cottage's for instance, is prohibitive !!!!
And what about termites ???
Owen Geiger (author)  vincent75203 years ago
There are many kinds of thatch and all range of prices around the world. Here in Thailand, 1.5 meter long thatch panels are 50 cents US$ (half a dollar). We used 200 panels for a total cost of $100. The panels are made of vetiver grass that's resistant to water and insects due to its waxy coating. Vetiver is very common around the world.
Vetiver thatch video: http://www.youtube.com/user/naturalhouses#p/u/14/iDzkGk_p6wU
We're experimenting with vetiver/clay earthbags and blocks. They were set on top of a termite nest for about 2 months with no damage.
http://www.youtube.com/user/naturalhouses#p/u/8/mksDJGnnPZM
There are other similar videos on the same site.
If you're in Thailand that's different ! …
Pricewise that is ! …
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