Here’s an innovative earthbag project to whet the more arty side of your appetite. Rhonda in our Mud Home Facebook group is making something rather stunning happen over in Mexico. This is an exceptionally well-designed build, with so many original architectural features, I wanted to showcase it. Rhonda was also incredibly informative in her documenting, which is very helpful for others, so a public shout out to her for that.
The Mexican Dream
But let's rewind a bit. How did this earthbag marvel begin? As always, it starts with a dream. Five years ago, after many visits to the country, Rhonda moved to Mexico. “I fell in love with the more simple way of living. Mexico taught me that all of the stuff I had accumulated in my past life in Canada and the United States was completely unnecessary, all the kitchen gadgets, 25 pairs of shoes, the matching set of pots and pans, everything that we think we can't live without or that we need to be happy.”
Oh and ain’t that the truth, eh? So our muddy artist ditched the Western fixation on ‘more more more’ and moved to Nayarit on Mexico’s west coast. “It’s the best decision I ever made,” she says. “There are always language barriers and issues that come up, but I happily accept them as challenges and experiences.”
We’ve been watching somewhat agog in our little Facebook group as this earthbag dome world has mushroomed out of the dust. Pretty much all you see below was built in the month of November. One of the greatest boons of the earthbag building technique is it boasts both strength and flexibility. You can do things with it that you can’t do easily with many other techniques. One of those architectural delights is the dome.
A Word on Domes
Now, before we go any further, and before a thousand more people rush out and decide to build a dome because hey they’re sexy, a word of caution. Domes are not for every climate. They pose many waterproofing issues for one thing, I'll be covering them in more detail next month, but in the meantime, don't say I didn't warn you.
“For many years I investigated different methods of more natural ways of building,” says Rhonda. “There seem to be more and more popping up these days, different ideas all very interesting in their own way. It wasn't until I read your book Mud Ball and found your website that I became really intrigued and started soaking up all the information I possibly could.”
Rhonda sculpts dolls for a living, so it’s no surprise she would want to work with earthbag, which like cob often attracts artists because both allow the builder to literally sculpt a house. You are no longer restricted to post and beam structures, or inflexible building materials. The whole shelter becomes something to mould.
“I love that it's possible to experiment and include lots of different techniques artistically like sculpting and painting and stonework, just to name a few. Really your imagination is the only limit,” Rhonda says. And let’s face it, this might be her first build, but her imagination is certainly enjoying some legroom, even so.
So how did she and her team build it?
“We did two levels of gravel-filled bags below grade, and another two levels of gravel-filled bags above grade. Black plastic was added over the bags after the below grade levels were finished,” explains Rhonda. She’s really chosen the correct foundation and stem wall approach. I’ve said it many times, it’s hard to beat the rubble trench foundation for natural builds. It simply works. It’s cheaper than Portland cement, a million times better for drainage, fairly fool-proof and a lot more environmentally kind. I can’t see one good reason not to use it.
More on gravel foundations here.
The Earthbag Domes
These domes are made from earthbag PP tubing filled with stabilised earth. “I went with continuous bags and 50cm wide,” explains Rhonda. "After the gravel bag layers, we continued filling all of the next levels with dirt and lime. We added some plumbing and are going to be separating grey water out for recycling,”
The domes will comprise skylights embedded into the top. In this case the upper ring of the dome (where the skylight will sit) has been reinforced with a small concrete ring (bond beam). Bond beams at the point where a dome tapers in are sometimes used (or required by codes) to prevent the dome from splaying out under the pressure of the domed roof. These can also be made from wood, which I prefer not only for eco reasons, but because wood typically has more give than reinforced concrete. In this case though, the ring is so tiny and tight, Rhonda is right in my opinion to choose cement. You'd be hard-pressed to make a structurally sound wooden circle that small. "The other reason I didn't use a wooden bond beam is because we have a huge termite problem in Mexico. They eat up everything in a matter of a couple weeks and the only way to keep them out is to spray with some very hazardous concoction," explained Rhonda. And it's true, sometimes Portland is the lesser of two evils.
The Keyhole Doorways
It’s not just the cluster of domes that is interesting in this build. For me it's the other features that are truly inspiring. I don’t think I’ve ever seen anyone make anything like Rhonda’s stunning keyhole doorways.
How did they make them?
The doorways are so clever. They were made using moulds that were engineered from tyres resting on wooden frames. The tyres were old disused ones, which made them a much cheaper recycled option than making wooden forms.
“I was able to find free tires for window and door forms and we wired two tires together for all of the window openings to make them wider because we're using wider bags. I'm using the tractor tires for the door into the indoor garden and one also going into the bedroom,” explains Rhonda.
This keyhole doorway is particularly exciting because it joins two intersecting earthbag domes.
“This first one, La Casa Montañita, will be my home and a very special build for me,” says Rhonda. But it won’t end here. It never does:) “I am planning to build on the same piece of property a Superadobe pool and a structure for art retreat and class students to stay in. I will offer and host classes for many types of art, sculpting, painting, doll making, stone mosaics and who knows maybe even Superadobe. I'm addicted to this method of building and it's countless possibilities. I'm sure there are many new projects in my future.”
Things to take away from this inspiring build:
1. Using wider bags: As Rhonda says, “I love the wider bags for the walls but it does make the work a lot heavier. We are also using an extremely heavy tamper and double rows of 35 kilo barbed wire so the bags are super solid.” When you use wider sacks in earthbag, it means you have to dig and fill a lot more dirt. But...wide tubes are going to be less of a strain than wide bags, because tubes don’t get ‘lifted’ onto the wall after they are filled. This is worth bearing in mind.
2. Stabilised earth: Take note, if you don’t have enough clay on your land for any reason, you can also stabilise your earth using lime in the mixture.
3. Planning and design: There are usually two camps: one lot spend their life overthinking everything and doing nothing (groan); the other bunch (ahem, me) leap straight in and muddle through, the downside being more potential cock-ups and extra expense (but hey, at least something manifests). Then there is this rather admirable subset of folk, of which Rhonda is one, who plan things superbly well, and actually execute their plans as well. I have nothing but respect for such people. For the rest of us, it pays to know which side of the overthinking/reckless-and-rash boundary you sit, so that you can push yourself in the other direction.
See more on Rhonda’s dolls here: https://creamsodabjd.com
Keep up with her sculpted eco builds here: https://www.smudgez.com
Related articles you may find useful
My Free Earthbag Building Guide: http://www.themudhome.com/earthbagbuilding.html
More on the polypropylene sacks: http://www.themudhome.com/the-sacks.html
Gravel/rubble trench foundations: http://www.themudhome.com/gravel-foundations.html
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