Earthbag domes in Vanuatu

Hello,
I arrived in Vanuatu a month ago and I plan to build 2 dome houses (1 dome and then the other one with two) for tourists and at last one 3 domes house for myself.
My main worry is about the rain and so I'd like to know how to proceed about making it all very water proof.
Thanks for advices.
Patrick

Seeing that Vanuatu is in an active earthquake zone, I would question the wisdom of building massive earthbag domed structures. Low walls, perhaps, with signficant bracing and wooden roof structures. What indigenous roofing materials are used? A well-sloped roof withadequate ventilation would probably be more effective and comfortable given the local climate. Also, what is the character of the soil you have? As a volcanic island chain, I wonder if Vanuatu has soils that will compact well in earthbag use.

Hi Glenn,

Thanks for your answer.
I was thinking about 6 m diameter for the biggest domes. Is that already too big?
It's true that natural roofs look good and here they use pandanus palms or other palm leaves but I really wanted to build only with earth bags; I can have earth filled bags mixed with sand and cement if necessary.
Do you know what would be the good proportions?
Wanting to build domes without classic roofs is not only because i'm hard headed, it's also because I'm on a tight budget and I thought in the future it might develop for other "poor" people here.
But I'm not stupid so if really it's no good to build domes here I'll do something else.
I have time and the other good thing is that labour is cheap here; I could easily have 7 to 10 people working with me (wich made me also think tubes would be better than bags).
I dug two wells on my land because I want to be able not to use corrugated iron roofs (uggly and dangerous when too much wind).
The land is pretty good on my lot; just have to look at the massive trees to understand anything will grow there. There is sand under the earth.
I can also have extra earth and sand delivered at low cost if necesssary.
To sum it up I'd say I really want to try these dome houses and I'll do anything to make it work.
Thanks for your time.

Patrick

You can build an earthbag dome and it will probably be strong and hurricane-resistant, but unless it is reinforced with steel according to professionally-calculated designs, it is likely to collapse in an earthquake and kill anyone inside. Concrete mixed with the soil will make it stiffer, but steel to tie it together is the only way to guard against the bags slipping and falling in strong shaking.

Go ahead and build a small dome to test, and see what it feels like inside in your climate. It may be more liveable than the local standard, or it may be less, I don't know. How much have you studied earthbag domes? What references do you have for safe dimensions, slopes, thicknesses, etc.? Do they consider earthquake resistance at all?

Another factor in construction is the foundation. Sand is not a good base for massive structures, as it may squeeze out from under the edges, does not resist lateral forces that a dome would create, and has a tendency to turn liquid in earthquake-type conditions. It is also not likely to be helpful in the bags except as mixed with cement; it will never harden by itself no matter how well packed it is (short of geologic time;) and will be extremely porous. What are you thinking of to make the roof waterproof? Earthbags alone will obviously not work outside a desert climate.

Hi Glenn,
Maybe I got it wrong from start!
I thought earthbag domes were designed to resist earthquakes and that the two lines of barbed wire between each row of bags were enough to make it resistant.
I watched a few videos, visited a few websites and bought Owen Geiger "Earthbag building guide", but I have no knowledge at all about architecture (I'm a photographer ).
I'm just looking for the cheapest and best way to build a house; my plan was to build earthbag houses because two of them will be used as accommodation for tourists and the fact that this building method is very unique, would be a plus to attract people. You know, the Hobbit house by the beach... with paradise garden and a natural pool...
Then I thought that because it comes out so cheap and because it's so resistant, more houses would be built for the local people; you heard about the Pam cyclone a few months ago?
Nothing stood where it ran. Local people build shacks with wood and palms; everything flyes away when there is too much wind.
Now what about if I build very small domes? Say 3 m diameter for the biggest dome and then have 2 m diameter for an extra dome or two...
Three small domes instead of a big one and at the end it's like a little village with small domes everywhere!
Some plaster would be used to cover the bags to make them water resistant and also give them a color; naked bags are pretty ugly.
I'll find out what the best mix is to cover the domes; plaster, waterproof paint,...
For the inside of the houses I was thinking about tamped earth.
Looking forward reading you; have a good day.
Patrick

It's true that domes are an inherently strong form, and barbed wire between bags may give adequate shear strength for minor disturbances, but a dome as large as 6m/20' is getting to the point of requiring more element strength than earthbags and barbs can give for a moderate earthquake. It might stand up, but if it doesn't, the results will be deadly.

A 3m/10' dome is significantly more stable; the forces on it will be less, and the bags are larger/thicker in proportion to the span. A cluster of these (touching) may even reinforce each other, I couldn't say for sure without an engineering study. I still think you need to try a small one for interior livability compared to vernacular housing. I suspect that ventilation will be very important.

Hi Glenn,
So, my 6 m diameter dome has become a 3 m diameter double dome, like an "8" (two 3 m diameter domes, joined) and where the two domes join, I plan to add a bathroom; say about 2 m diameter with 2 m high walls without a roof. Maybe we'll build a wood and palm leaves little roof that would cover half the bathroom surface so we can use the bathroom when it rains and stay dry... The shower area would be under the open sky part as it doesn't matter to shower under the rain

Next stage is about the plaster to cover the outside surface of the domes; I understand this has to be very waterproof.
Do you have any info about this?
Special mix plaster? Waterproof paint? Both?

As I see it now, I imagine small earthbag domes, linked together for strengh with lots of deck area in front.
I mean here we tend to live outside as it's warm all year long and we need to go inside only to sleep.
So I plan on lots of surfaces of wooden decks with natural roofs (palms, the local way) and little alleys to go from one house to the next.
At the end it looks like the smurf village or some hobbit village thing.
Something like this: (the writing you see on the pic is Thai; I'm not sure wether these houses were built in Thailand or not but I know it rains a lot there, so ther should be a way...)

Just saw this old thread which has a bunch of discussion and information on earthbag construction. Apparently California does think they are earthquake resistant. I still wouldn't make a 6 meter one, at least until I was experienced with the technique. The risk of failure and the consequences are too great. The character of the soil is important; some kinds (sandier) simply will not compact as well as others.
https://permies.com/t/3277/earth-bag/dirt-bag-structures

Hi, there are several earthbag homes and water tanks in Vanuatu that have been built since 2012. If you visit the sites around Port Vila you may get a better idea of what you want to build. All of the buildings are certainly strong enough for a category 5 cyclone and small tremors. There are trained earthbag builders in Efate, Tanna and Santo who would love to get some work building if you need some help. We will be helping with a big build near mele in December. This will be our 4th house over there.

The first house we built was round and I can tell you it wasn't well received by the locals. They really don't like the round houses. We didn't do conical roofs because of the problems in a humid climate they become quite damp on the inner walls. Let me know where you are building and if you need any help.

Hi,

We plan to build on Aore island (just in front of Luganville, Santo) where we bought our lot, on the beach.
We are thinking about building a first house with two domes of 4 m diameter each and we also think about a wooden and palms roof instead of earth bags up to the top.
There would be a bathroom nested at the intersection of the two main domes.
First thing is to get a building permit, so we have to make up our minds on this one wich is not easy as the more we get informations, the more we change our plans!
First idea was a 6 m diameter dome with only earthbags up to the top...
Of course any info will be appreciated.

There are two women's water tanks there built with bag tubing, I think one is at hog harbour but it should be easy to find if you ask around.

Lesieli Joseph runs Vanuatu Earthbag building as a not for profit from Port Vila and I support her work from sydney. With 4 houses 12 water tanks and all the land issues that go with it we have had a steep learning curve. We have had engineers and university professors helping us overcome some of the problems and helping us utilise some of the natural advantages. If you use the coral crush or local pusee for building it will become rock very quickly. Topsoil over there is too good to waste in bag fill.

We would be happy to help you in any way with advice or contacts. It would be great if you could benefit from the mistakes we've made. Earthbag houses are amazing but once you've built one there is no easy option to knock out a wall or make alterations.

You can message us through the Vanuatu Earthbag building Facebook page.
We will be there in a few weeks.

Glenn Herbert wrote:You can build an earthbag dome and it will probably be strong and hurricane-resistant, but unless it is reinforced with steel according to professionally-calculated designs, it is likely to collapse in an earthquake and kill anyone inside. Concrete mixed with the soil will make it stiffer, but steel to tie it together is the only way to guard against the bags slipping and falling in strong shaking.

Go ahead and build a small dome to test, and see what it feels like inside in your climate. It may be more liveable than the local standard, or it may be less, I don't know. How much have you studied earthbag domes? What references do you have for safe dimensions, slopes, thicknesses, etc.? Do they consider earthquake resistance at all?

I recently read Bingham's book and follow her blog. Her new construction survived 4 earthquakes from 5.2-6.1. Her construction is a round house, which I feel would be more suitable to withstand earthquakes over a dome. Also, she did not use any concrete in her bags. http://www.themudhome.com/earthquakes-and-earthbag.html

Dr. Gieger has a number of articles on his sites concerning earthbag constructions and earthquakes. I would look around that site some more.

Hi Gregory,

Thanks for your time.
As time passes we keep changing our minds about the house we are going to build and we are going to build three!
Today we think the best is to build a first house as follows:
1 dome of 6 m diameter, 1 dome of 5 m diameter and a bathroom where the two domes join each other.
The main change is about the roof part; we now think we won't do full earthbags domes but only the walls and then we'll build wodden frame to hold natangora roofing (some local sort of palm leaves).
So, the new problem is that we need to plant some poles into the ground and ceiling high so we can fixe the beams for the roof on them.
The problem is where are we going to plant these big poles?
Inside the walls, between the bags? I don't like the idea as it poses a problem with the barbed wire that is supossed to go all around the house.
So, should we plant these poles inside the house or outside?
Is it possible?
I bought Geiger's book and looked trough some website and forums; luckily I have plenty of time before I start building and the advantage here in Vanuatu is that I can employ up to 10 people to help me.
Last thing; the lot I bought is a bit sandy and I wonder if it needs to be stabilized...

Cheers.

Patrick

P.S/ and happy new year!

Hi Patrick,

Can you better describe or make an illustration of your issue with the poles? I'm not following.

As far as earthbag construction books, I still feel that Hunter/Kiffmeyer's "Earth Building" book is the best out there. I used it for my project as someone completely new to earthbag building and my dome came out relatively good.

Have you done a simple jar test to see the composition of the soil?

Hi Gregory,

The poles I talk about are necessary to hold the roof to the ground; they are planted verticaly into the ground (5 poles make a pentagone, 6 poles make an hexagone, etc...) and the top of each pole must go a little higher over the top of the walls so the roof can be attached to someting.
My problem is to find the best place to locate them: inside the house, along the walls or outside or whithin the walls (wich I don't like because of the barbed wires that are supposed to go all around the house).
The earth on my lot is very sandy but I have also sand and coral bits that could be used; I could even get better earth delivered by truck if necessary.
Cheers.

Patrick

I'm still not getting it. You can include wood plates between the bags and have them sticking out as attachment points for framing outside the dome. From there you can attach a more traditional style roof. I don't see the need for poles for anything.

In my readings on earthbag construction (or other masonry) and earthquake resistance, is the use of wire mesh (chicken wire) on both the inside and outside of the structure, and connected between the walls.
The wire needs to be pulled tight to prevent motion of the masonry or eathbags. When properly applied, this method far exceeded the california earthquake testing equipment. That said, Im not an engineer and cannot educate you on the proper way to build. I mention this to give you a starting point for your own research. Please consult a professional engineer in such a high danger area.

Ash Medai wrote:In my readings on earthbag construction (or other masonry) and earthquake resistance, is the use of wire mesh (chicken wire) on both the inside and outside of the structure, and connected between the walls.
The wire needs to be pulled tight to prevent motion of the masonry or eathbags. When properly applied, this method far exceeded the california earthquake testing equipment. That said, Im not an engineer and cannot educate you on the proper way to build. I mention this to give you a starting point for your own research. Please consult a professional engineer in such a high danger area.

Wire mesh, especially on domes, is tricky to work with. It slowed my team down quite a bit. We used chicken wire more for plastering purposes than wall strengthening. After we completed the walls, I realized that the walls and structure as a whole was and still is extremely robust, with or without the chicken wire.

I did read about another technique used in the book I used for my construction which involved lacing the layers together by using barbed wire hung from bricks and slinging them over each layer. It's a poor description, but is fully outlined in the book. If stability was a larger concern, I might consider doing something like this. It would add quite a bit of time and materials to the project though.