​Domes have been an integral part of human construction for a long, long while. From the mosques of Istanbul to the basilicas of Rome or Moscow, from adobe vaults in Mexico to the snow igloos of the Arctic Circle, the curved roof can be found in an awful lot of places. So that must mean it’s great, right?
 
Hmm. There’s a lot to like about the dome. There’s a lot to be wary of, too. And there’s a very good reason it was only the Inuit of certain areas who built igloo snow domes. Others further south used other techniques. It's not just coincidence that the mud dome was traditionally built in places like Cameroon or Mexico, but not in Cornwall or Galicia. Dreaming of a mud Sistine Chapel in your back garden? Read on.

The dome became something of an architectural darling in the ’60s. A lot of this has to do with Buckminster Fuller, who began pioneering geodesic dome structures and biospheres in the ’40s and ’50s. A decade later domes became popular on a more individual homeowner level, when space-age architecture became trendy. This is also when the limitations of the dome as a house became clear.

The Good
Domes are beautiful for sure, and they feel extremely calming to live inside. They are like wombs or caves. And heck, for an artist they're both original and funky. With their soft lines and circular form they soothe both eye and spirit. But beware, like most sexy things, they come with some potentially costly drawbacks.
 
The Bad
Lloyd Kahn of The Shelter Blog wrote two books on domes. They were his most popular and lucrative publications. Yet he pulled them off the market because, to quote him, they were “smart but not wise”. Here’s a list of reasons why:
 
1. Impractical
One interesting issue Lloyd Kahn has with domes is that they are impractical. You can’t dissect them easily into sub-quarters, meaning they’re great for meditation centres or lecture halls, but not so great for a house, where you might want to cut the space up into separate rooms.
 
Solution: Well, I suppose here I’d say if everything had to just be practical in this life, I’d probably hang myself from boredom. That isn’t to say Lloyd doesn’t have a good point. I experienced the same issue on a lesser scale with my roundhouse. Pretty much all building materials are designed for squares. And you’re probably going to be making your own furniture if you go dome. But as far as the separate rooms are concerned, if your heart is set on round then the solution is to build multiple smaller round spaces that are linked, like Rhonda did here in Mexico.

2. Leaking
One of the more serious disadvantages of the dome is they are notoriously difficult to waterproof, because unlike most housing structures, there's no roof, and therefore no 'hat' to protect the structure. This is fine in a desert, and even more fine if you only have soft powdery snow sitting on ice blocks. But bring in some serious rainfall, and you’ve got major problems. For the geodesic domes there are masses of joints where the triangular panes all tessellate, all of which are potential leak points. That’s a lot of sealant you’re going to need, and a lot of potential maintenance.
 
For mud domes, in particular earthbag domes, water-protecting is the thing you absolutely have to wrap your head around. Because what you really don’t want to do is what every mainstream builder will tell you to do, namely coat it in Portland cement.
 
Don’t cement over a mud dome!
If you slap Portland on, you have basically stuck an impermeable crust over your lovely breathable walls. So you’ve just killed the airflow. Boom! This will lead to an increase in mould and damp. The house won't be as cool in summer (or warm in winter) as it would have been if it were all mud.

Also, there’s a reasonable chance the cement will crack and fall off too, as clay walls expand and contract with humidity changes, while Portland can’t. See this experience kindly shared by Gautam. Please note this was lime render not Portland, but basically it's the same issue (though at least the lime render will breathe). http://www.themudhome.com/.../gautam-and-kims-earthbag..

Proper solutions:
There are two main ways to keep a dome dry:
 
1) Do what Jehane Rucquoi did at 3 Moons and build a deck on it, or add some sort of cap over the top. This is easily the best way to protect the dome. Jehane's design was ace if you ask me.
 
2) Use shingles. See more about them here: https://en.wikipedia.org/wiki/Roof_shingle
 
Yes, domes are a tough one. But I'm not going to lie, I'll probably make one before I die, because for a creative soul they are beguiling structures.

Related links:
 
Kelly Hart’s interview with Oliver Goshey, all about earthbag domes. A must-listen if you are considering building one! https://abundantedge.com/abundantedge-xzmogh2g479mqg866e0v765lb804l6
 
Lloyd Kahn interview, where he discussed the limitations of the dome: https://www.buildingsustainabilitypodcast.com/45-years-of-building-inspiration-lloyd-kahn/
 
Rhonda’s dome world in Mexico: http://www.themudhome.com/mudbuilding/rhondas-sculpted-earthbag-dome-home-in-mexico
 
Jehane’s earthbag domes in Nevada:
http://www.themudhome.com/mudbuilding/the-85-year-old-dome-builder-of-arizona
 
Do you enjoy The Mud Home?
If you find these articles inspiring or useful please consider joining us on Patreon. Your support pays for the running of this website, my virtual help, and my sustenance. A big thank you to all The Mud Sustainers, and everyone chipping in and keeping these posts and articles coming.

​It’s actually pretty easy to add window and door frames into earthbag buildings. The most important thing, as always with earthbag, is anchoring things to the walls. But there are a couple of potential issues, so it pays to be aware of them.
 
1. Making a mould
The standard way to create space for your door or window is to make a mould. Some people use tyres, some use hay bales, most build a box out of wood or ply and insert it onto the wall where they want their window. 

That said, I’ve never done it this way. I’ve always stuck the window or door frame straight into the wall, and built around it. There are pros and cons to both methods, as you’ll see in a bit.

2. Anchors
As you lay earthbags up to the edges of the mould or frame, it’s crucial to add anchors between the bags that you will attach your frames to. What you don’t want in any kind of construction is the frames shifting or sliding about. They need to be securely nailed into the earthbag wall. How?
 
You can either make your own anchors from small planks of wood and slot them between the bags like this:

Or you can use metal brackets to do the same job (see Owen Geiger’s method).
 
3. Fixing anchors onto earthbags
Fix the anchor onto your earthbag by driving big fat nails (minimum 10 - 12cm) right through the anchor and into the earthbag.

​I’ve found you want one anchor, every three or four rows of earth bags. Any less and things start wobbling.
 
4. Barbed wire
Once your anchors are secured, you lay the barbed wire over the top of the anchors, and nail it into place. This gives the upper row of bags something to grip onto. Once you tamp the lot down, that anchor is wedged. Now you have something to screw/nail your window or door frame into.

​Issues to watch out for:
The snag with earthbag is this: The higher up you go and the more you tamp, the more pressure is exerted on the lower bags. So they will naturally squeeze inwards, pressing against your window or door frame, or indeed your mould. If you are using a mould this can make it difficult to yank out. The common recommendation is to stick wedges between the mould and the earthbag wall. Even so, most people still seem to find it hard to pull the mould out. A mould without rough edges will help your cause. Or perhaps a bit of plastic sheet between the wall and the mould would help it slide?

​If you want to add window or door frames directly into the wall, your issue is this: Your frames must be tough or they will buckle under the pressure of the bags. This happened on my first house, where the window frames turned into trapeziums :)) You need to pay attention that your lower, upper and side lintels are heavy-duty, because they all bear the brunt of the pressure. We used 10 x 30 cm lintels on the build in Olympos, and they held up.
 

Good luck folks! And remember, everything has to be anchored together in earthbag building. If it's not anchored into your wall, it's not secure and may well wobble.

Do you enjoy The Mud Home?
If you find these articles inspiring or useful please consider joining us on Patreon. Your support pays for the running of this website, my virtual help, and my sustenance. A big thank you to all The Mud Sustainers, and everyone chipping in and keeping these posts and articles coming.

​Starting Your Own Project?
The Mud Home 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.

​ (With details of how Cath made her super living roof)
 
Time for a different earthbag build. I’m letting you in on a mud adventure that has touched my heart rather. It’s one you won’t have seen before. Deep in the urban badlands of Brixton is a mud home with spirit. It’s plucky, original, and despite its size has plenty of personality – much like the woman who built it, in fact. Welcome to Mud Hut, built by Cath Coffey and the Mud Hutters.

For those outside the UK or who don’t know, Brixton isn’t some rural off-grid wilderness, it’s London. But while Mud Hut squats in the capital’s backyard, it harks back to somewhere else, somewhere much further south. Its roots stretch right back across Europe, over the Mediterranean, through the Sahara, and into East Africa.

“I always loved visiting my grandparents in Kenya,” Cath told me. “They lived in mud huts in a village on the foothills of Mount Kenya. My grandfather had two wives, each with their own hut, thatched with reeds from the river. Kids, goats, chickens and wood-fired cooking smells all intermingled. The sound of Kikuyu and laughter...It felt like a free life, if a strenuous one. They grew their own food, and were mostly self-sustaining.”
 
And it was this Kenyan life and family that inspired Mud Hut.

Mud Hut is 22 feet in diameter. It’s an earthbag house (hyperadobe) with rubble trench foundation, earth plaster, and wooden floor. The house was made with raschel mesh tubing, which Cath found from a certain Mr Jing Hou in China. “He was the only person I found who would send me a small quantity (500 metres),” explains Cath. “I still have plenty enough left for another structure or two! Mr Jing Hou loves the building...calls me Mr Cath.”  :)

How long did it take to build?
“The house took just over a year to build, and that includes a long break for winter. It was constructed by myself and one other helper mainly. Del McCoy was my main wingman. The rest of the family were also amazing, each in their own way. I’ll always be indebted to friends who took time from their busy lives to help. It was a very special time,” explains Cath.
 
How much did the house cost?
“Honestly, I don’t know and I’m scared to total it up! I know it cost a lot more than I thought...scrub that...I didn’t think about the cost. I just had a compulsion to build.”

​How to reduce the cost of your build
On the subject of cost, one thing I can say is that Cath is super smart about reducing building costs by using recycled and reclaimed materials. It makes a huge difference. I often think that with building as with travelling, you spend as much as you have. Do take note of Cath’s tips on foraging below, especially if you are in a first-world country where people shamelessly throw everything away.
 
How Cath made the living roof
Living roofs are always made like massive club sandwiches: there are plenty of layers. Cath really did her homework when it came to the roof. It’s designed for a cold, wet British climate.
 
1. The roof has a wooden frame (60% off from a family member who worked at a large DIY store).
2. The frame was covered with free reclaimed 18 mm plywood.
3. Next layer was carpet from the bins at the back of Carpetland (pure wool!)
4. Then Cath added 6mm EPMD pondliner (expensive).
5. After that there’s a root barrier (root barriers are always non-organic, otherwise obviously roots will burrow and your roof will no longer be waterproof.)
6. Finally sedum modules with Leca (expanded clay balls) infill.
 
“I know from my sedum roof at home that the sedum will eventually migrate and colonise the Leca. The carpet, sedum and Leca all make for good insulation. There is also 150 mm insulation batting in between the roof joists. The building is both warm and cool when you need it to be. Result!”
 
The pitch of the roof
People sometimes get this wrong, because unlike tiles or other roof systems, living roofs don’t want too much pitch. If the roof’s too steep you’ve got erosion issues; if it’s too flat you’ve got a swimming pool. About 5 - 10 degrees is optimum (that’s 1:12 or 2:12 max).
 
What about the edging?
This is the trickiest part of the living roof, if you ask me. Cath’s living roof is edged with steel garden edging. The EPDM is sandwiched between two layers of edging so that excess water drips off the lower edge. She plans to build planters with water-loving plants at the drip edge to take advantage of the run-off.
 
This is definitely a super model for a living roof on an earthbag house in a wet climate, in my opinion.

​What was the most challenging part of the build for Cath?
“The doubt,” she replies. “The ‘do I know what I’m doing?’ The physical demands; earth is heavy. The protracted time period. Costs spiralling. The ups and downs of life.”
 
Mud Hut Today
Cath built this house for her artist sister, in fact. “She’s a compulsive maker and needed space.” And what a beautiful place for a creative to work within! It’s the ultimate she-shack.

​Cath’s Resources:
Cath has kindly shared the resources she used to build Mud Hut.
 

• The late great Owen Geiger of the Natural Building Institute. “So generous with his  responses,” Cath says.
• Earthbag Building by Kaki Hunter and Donald Kiffmeyer.
• YouTube: A valuable resource full of generous people sharing their experiences. Great for people who learn best by watching.
• The Mud Home and yours truly (blush).

 
On the subject of Owen Geiger I’ll also pay tribute, because he patiently answered my questions too, and whenever I’m feeling a little frustrated by my inbox, I always remember his generous example.

Do you enjoy The Mud Home?
If you find these articles inspiring or useful please consider joining us on Patreon. Your support pays for the running of this website, my virtual help, and my sustenance. A big thank you to all The Mud Sustainers, and everyone chipping in and keeping these posts and articles coming.

​Hold on to your seats. I’m about to blow your mind. I’ve just witnessed the most stunning clay plaster I’ve ever seen. It’s on an earthbag house too, which I can tell you is one of the trickier substrates to achieve a decent finish on.
 
The masterpiece in question is courtesy of the wonderful Geeli Mitti community in northern India. Geeli Mitti was founded by Shagun Singh, who is pretty much as incredible as her houses. What she has created up there near Delhi is nothing short of a dream. 

​This earthbag house is the latest in a number of revolutionary architectural projects at Geeli Mitti. Shagun and friends love experimenting with different kinds of natural building, and have perfected clay plasters to such an extent, I’d rate it as some of the best out there. And that’s no exaggeration.
 
I’m a bit lucky because Shagun is a member of our private Facebook group, so I was able to get some details on how these colours and finishes were achieved. It’s all surprisingly simple.

​I originally assumed this was a clay paint finish, but I was wrong. “No paint used,” explained Shagun. “It's the finish plaster coat itself on the exterior. We used red clay soil dug out from a nearby land, and similarly some whitish-yellowish soil that had been dug out, then added some yellow oxide minerals to it to achieve the colour.”
 
Yes, amazingly and wonderfully, this beautiful result wasn’t achieved by importing a bunch of materials, but by searching out and using clays in and around the structure itself. This is so often possible. Unless you’re at the beach, it’s highly likely you have many different types of clay in your neighbourhood, and it’s worth hunting for them because you don’t need huge amounts for a finishing layer of plaster.

​“On the inside, we lime washed the walls with the yellow oxide added to lime,” says Shagun.

​But what about this truly eye-opening Shiva sculpture? How was that finish achieved?
It's actually a clay, sand, dung mixture sculpted into shape. Then, once the sculpture was completely dry, it was sanded smooth with sandpaper. After that it was coated in linseed oil for sheen, hardness and weather protection. Nice huh?

This guy is a real masterpiece. I wondered how Shagun and friends achieved the milky finish. “This finish plaster was a mix of our site soil which is 60% sand, some clay to balance it, cow dung and very little lime. The lime to rest ratio would be 1:6 and then once the plaster was still slightly moist, not completely dry, I burnished with crystals using small circular motions. So lots of elbow grease needed,” says Shagun.
 
As you see, the mixture itself is incredibly simple. It kind of proves why I’m skeptical about adding a million things to your earth plaster. The application technique, along with perseverance and  effort, is at least half of the story.

Over the course of time, some of the Geeli Mitti team have become real pros. "I'd love to mention the name of one of my oldest team members, Ganesh," says Shagun. "He has worked with me throughout on all the plasters and finishes showcased in the article, and has become quite the plaster wizard now!"

​If you think Geeli Mitti is content to rest on its laurels here, you’d be wrong. They’ve already got another ground-breaking project organised for the end of May. What’s next? A bamboo geodesic dome! So if you’re in northern India and want to experience the Geeli Mitti natural building phenomenon, I’d sign up for that course quick.
 
More about Geeli Mitti
You can find out more about Geeli Mitti from their Facebook page or their website: http://geelimitti.in/
Do check out “The Team” page on Geeli Mitti. I love that the animals are placed at the top of the team, and the cooks are second. Sounds exactly right:)

Are you building or planning to build?
If this is you, consider joining The Mud Home Facebook Group. It will no doubt save you a bunch of money, as many have already commented. You also have the chance to connect with some amazing natural builders and off-gridders. The numbers for that group will be limited to 100 so that I can give the proper attention to each project.

Do you enjoy The Mud Home?
If you find these articles inspiring or useful please consider joining us on Patreon. Your support pays for the running of this website, my virtual help, and my sustenance. A big thank you to all The Mud Sustainers, and everyone chipping in and keeping these posts and articles coming.

​Arches are a lot like Amal Clooney: Smart, well-put together, and began life in the Levant. Some of the first arches (as far as we know) were constructed around 2000 BC in Mesopotamia, and as anyone who has wandered round an old Roman ruin will tell you, an arched doorway is often the only thing remaining after an earthquake.
 
Arches work because any external pressure pushing inwards or downwards on the arch stones only serves to compress them tighter. But...before you leap up in arch-building excitement, there are a couple of points to etch onto your brain.
 
Before starting an earthbag arch remember...
1. Earthbag arch wedges need to be a bit wedge shaped, and must be jammed in tightly, otherwise the arch principle doesn’t work.
2. As the forces of the arch push down to the ground, the arch will push outward at the base. So, you need some decent ‘abutment’ (aka a good fat earthbag wall on either side of the arch to stop it pushing outwards).

Here’s how to make an earthbag arch, step by step
 
1. You need a mould or strong arch frame to lay your bags around. In our small arch, we were incorporating part of an organic tree trunk, so the arch wasn’t perfectly round. On a small arch this won’t matter, but a larger one needs more precision.

2. Attach a piece of string in the centre of the bottom of the arch. You use this to check the angle of your arch wedges.

​3. Make a wedge mould for your earthbag 'slices'. Stick your empty earthbag in the mould, fill it with clayey dirt, and tamp it firm until you have an earthbag the shape of a slice of brie.

​4. Arrange your bag wedges around the arch. Use the string to check they're lined up correctly. Remember, if your bags are not wedge-shaped but straight-edged, they’re not going to compress together. As you lay the bags, weave the barbed wire in and out of the wedges (see top photo). Make sure the wedges are tightly jammed together.

5. Once all the earthbag wedge pieces have been jammed in, time to drop the keystone in the middle. It may end up being more of a squeeze and shove than a drop, but as long as you've jammed the keystone piece in nice and tight, it will hold.

6. Run a course or two of barbed wire over the top of the arch, and lay another layer of flat bags over the top of the arch to lock it all in.

Extra note from the Costa Rican Earthbag Team
 
Our Costa Rican team in The Mud Home FB group made the wide and beautiful earthbag arch in the top photo. Because of the span, I asked Murat if their arch technique had differed from mine in any way. “At the core, our method was the same, but we interwound/integrated a lot more barbed wire and aimed for super symmetry just because of structural demands,” Murat said. He also drove in a bunch of rebar just to make sure the whole thing was pinned together invincibly.

Are you building or planning to build?
If this is you, consider joining The Mud Home Facebook Group. It will no doubt save you a bunch of money, as many have already commented. You also have the chance to connect with some amazing natural builders and off-gridders. The numbers for that group will be limited to 100 so that I can give the proper attention to each project.

Do you enjoy The Mud Home?
If you find these articles inspiring or useful please consider joining us on Patreon. Your support pays for the running of this website, my virtual help, and my sustenance. A big thank you to all The Mud Sustainers, and everyone chipping in and keeping these posts and articles coming.