Step 17: Conclusion

Picture of Conclusion

Domes are the strongest form in nature and easily support enormous forces. We added about 20 truck loads of soil on the dome without it moving one bit. I’m confident another 100 truck loads could be put directly on top and it wouldn’t make any difference, because the dome is all in compression, and tamped earth (road base in our case) can support very high loads. So if you want to build underground, domes are a good way to go – that or roundhouses. Both gain their strength from the circle: forces (loads) are transferred directly to the ground. There are no components to fail as in post and beam or wood frame walls.

Domes have lots of other advantages. They create the most floor space for a given length of wall. There are no wasted corners. The feeling inside is magical. Those who live in domes (and roundhouses) most likely never live in boxes again. Wind flows around domes and does not build up pressure against them. You can build domes without wood. You can build domes with minimal tools and materials – no nails, no wood, no plywood, no shingles. This makes domes a good candidate for those who lack carpentry skills and for emergency shelters for disaster areas and war refugees. Give people some rice or grain bags and a little training, and soon they can build their own sturdy, safe shelters.

But no building system is perfect for all climates and situations. For instance, domes are not culturally accepted in some areas. Domes evolved in desert regions where wood was scarce, and are not the best choice in rainy climates. They’re exposed to the elements and vulnerable to leaks. It’s difficult to get a perfect plaster job that doesn’t leak. A leak could soften the soil and cause the dome to collapse, so the fill soil has to be stabilized, which adds to the labor and expense. For this reason we typically advise against domes in rainy climates, but this is not to say it can’t be done. There’s a dome in Koh Phangan, Thailand where it rains almost constantly for months at a time, and it hasn’t leaked yet. It was built by Phangan Earthworks with expert plasterer’s. However, few people can match this skill level, even those who do plaster work for a living. Plastered domes are particularly risky where there are freeze/thaw cycles. Water will get into every little crack (plaster always has small cracks) and burst the plaster when it freezes. That’s how nature turns mountains of stone into sand and gravel…

So the choice is yours. Domes are enormously popular among earthbag builders. If you live in a rainy climate, you could build a dome with a living roof like we did. We’ve had no leaks so far. Another good option is to build a roofed dome like the Kentucky Dome Home .

Photos: Meemee Kanyarath
lsuydam1 year ago
I LOVE this. What do you think is the largest dome you could build this way?
Owen Geiger (author)  lsuydam1 year ago

Somewhere around 20' interior diameter is about the limit. That would be 23' exterior diameter.

This is a beautiful structure. I would love to see the inside. How do you think this would hold up in New Jersey? We have a wide range of weather conditions 12 inches of rain last week and 2 feet of snow 3 months from now.
Owen Geiger (author)  yikesitsmindy4 years ago
It should hold up just fine. Raise the site well above flood stage, slope the ground away from the dome, use gravel bags on lower courses and use EPDM rubber membrane over the top. Be careful not to puncture it while adding soil on top.

For even greater durability, you could add lime or cement to the soil mix. Stabilized soil will hold up even under water.
hohum4 years ago
Might you consider an intern for your next project---ME

I am tired of paying rent,

I can do:
stained glass
built a COB wall
chair caning
wood working

gear hob
most any hand tool

fast learner.

cava0024 years ago
Awesome! hope some day I can make one
bvis4 years ago
First off, Cheers Mate! This is top notch. The Whole family wants to build one as a project. I was wondering though. Is it possible or feasible to fill bags with any medium? I was thinking perhaps plain old dirt, as I have plenty of that laying around. Maybe use pavement grindings from the city, their practically giving it away free. You mentioned wicking, maybe this is reason you went gravel. I just know that it would be costly for that much gravel here. Any Advise would be great.
Owen Geiger (author)  bvis4 years ago
Thanks. Glad to hear this is useful.

There's no limit to what you can put in the bags, although some things work better than others. Avoid large, sharp materials that can rip the bags. Sometimes loose sand will slump and create unstable walls.

Don't use materials in lower courses that wick moisture. Example: crushed concrete will wick moisture. Grindings of asphalt pavement would work great in lower courses.

Yes, gravel drains away moisture. That's why it's typically used in rubble trenches and lower courses of bags.

Rubble trenches could be filled with crushed and broken concrete. This often available for free from excavation companies or concrete contractors who tear out old concrete.

Soil: Most types will work. Look for subsoil -- the soil that's underneath topsoil -- that has a mix of clay and aggregates to make solid earthbags. Make a sample bag so you'll know if your soil will work. Often reject soil like caliche or 'fill dirt' from excavators is fine.
bvis bvis4 years ago
More digging through your sites/posts cleared things up for me on this question. Again Awesome structure!
Lurker4 years ago
You are using an equilateral pointed arch or lancet arch with corbelled construction. Have you considered using a radial (traditional sloping) construction on the same arch? Admittedly, tamping at an angle could be tricky on the upper rows but it might do away with the need for barbed wire and would seem to be stronger. What are your thoughts on this?
Owen Geiger (author)  Lurker4 years ago
That doesn't work. People tried that 20 years ago in the early development stage.
gkellett4 years ago
Fantastic. Very inspirational
Owen Geiger (author)  gkellett4 years ago
PikeMinnow4 years ago
It looks like from The Shire, in Tolkien books!
bellyboy4 years ago
the last pic is the best

tnx for sharing
Domes are indeed one of the strongest shapes. It is no coincidence that the Parthenon has stood the test of the elements.
Owen Geiger (author)  AlternateLives4 years ago
That's right.
slamfist4 years ago
its people like you that make the world better for everyone to live in!! if only they allowed things like this to be built in the "modern" world. the bylaws and codes would never allow this to be built here.. but im really interested in maybe a stealth shed down the hill
Owen Geiger (author)  slamfist4 years ago
Thanks. I show the low cost, low tech way. But you can do something similar and upgrade to meet code.
This is amazing! I will be looking into our codes to see if this will require permits... 5+ stars!!
Super Like! :)