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.
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.
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:
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.
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..
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.
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:
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