I stumbled on Earthships decades ago thinking gosh....wonderful but backbreaking... and with 4 ruptured discs that have since been repaired-ish... i dont see myself getting one done the ol fashioned way.
But, even if I can't pound tires. Maybe i can get enough mass with aircrete?
in truth, the monolithic dome is my favorite idea, but I can't afford all that shotcrete, and you can't really shoot aircrete without destroying all the bubbles.
So I began to think. What if i could combine the dome idea with tires? What if i could fill the tires with aircrete instead of dirt and just use more tires and build a dome by stair-steppin them inwards a bit at a time?
I could then slump a bunch of aircrete and dirt on it to keep it nature friendly.
Mechanically, that's a really interesting idea. I would surmise that there would have to be a way to tie layers together for shear strength, or to do the pour in one go so that the 'crete is monolithic contained within the tire framework. But the initial construction of the tire dome would be fun and look very cool.
Environmentally and practically though, I have issues with the probable outcome.
When Garbage Warrior first came out I was super stoked on Earthship. The fact that it doesn't work in my biome aside, I thought it was a great repurposing of materials and smart use of thermal mass. To a certain point that is true.
Then I started learning more about the increase of off-gassing from car tires as they age. They actually off-gass volatiles (and release solubles) more as they age. If you could encase them entirely with a air-proof barrier then they may be appropriate for an enclosed living space, but not until then. It's also worth looking into the trouble Biosphere2 had with persistent CO2 release from their concrete foundations. They were actually dangerously low on Oxygen at one point and had to break the dome's seal in order to breathe.
That leads me to think that this idea has traction in a non-living space. Shed, storage, etc, but not in a inhabited or food storage area: greenhouse, root cellar, etc.
After working on some projects in California, Vermont and here in the Yukon, I've really come back around to cob and super adobe. Super adobe especially doesn't have to be back breaking... but it sure ain't fast either!
Aircrete doesn't have the compressive strength by itself. Tires add tensile strength but little compressive strength. What makes earthship strong is the pounding of the dirt until it is fully compressed.
I think one needs to look at the local waste streams to find an appropriate solution for your climate.
My father in law's neighbor built a house with those 2x2x4 foot concrete retaining wall blocks. The local concrete plant had a whole yard of them they poured with any leftover concrete. It was a waste stream that he took advantage of. I want to use them for an earthship.
"You must be the change you want to see in the world." "First they ignore you, then they laugh at you, then they fight you, then you win." --Mahatma Gandhi
"Preach the Gospel always, and if necessary, use words." --Francis of Assisi.
"Family farms work when the whole family works the farm." -- Adam Klaus
In my experience, Earthships are great to live in and look at!
But they are a bit like elephants, nice to look at, but shocking to build.
On all building systems I believe earthships are the physically the hardest and seem to rely on very low cost labour.
I think its called 'cheap' labour in North America.
Or you run a series of workshops and get others to pay to help.
My cynicism shows.
Shifting the soil and pounding it into the tyres is very hard and slow.
I have experimented with bottles, loose soil, and rocks inside tyres as fences.
I screw the tyres together and have each column containing the same size and type of tyres.
They work ok for a fence 4 feet high.
There are conversations about whether tyres are safe to use, I have not been concerned about them, but it would be wise to read up about it.
Collecting the tyres can be hard, because they are bulky.
John Daley Bendigo, Australia
The Enemy of progress is the hope of a perfect plan