Earthships Chronicles
Part II: Earthships: Design & Build
“Achieving Sustenance in the face of earth’s phenomena”
— that is the ethos underlying earthships’ design, as elaborated by Mike Reynolds — father of earthships — in his introductory class. Mike used the tree as the example by which he has modeled his earthships’ design after. The ultimate goal is to achieve Sustainable Autonomy For Everyone (SAFE). Given the ongoing affordable housing crisis in many parts of the U.S., as well as rising cost of living, there is also the added incentive to address housing and energy insecurity made worse by the global pandemic.
Sounds fantastic! I can get behind that. But glossy brochures and website graphics aside, does it actually work as advertised?
There are 6 core design principles of earthships that have been formulated over the past 45-some years of trial and error experimental building — and it is still ongoing. I will give my reflections on each principle based on what I learned at the academy, conversations I had with my classmates and the staff and crew, my own observations, and other resources I’ve come across.
1. Using Natural and Re-purposed Materials
The cans and glass bottles are a quintessential earthship look. Though if it really bothers you, you can just plaster over them too. The tires — though not visible once completed — form the all important thermal mass walls. The tires, cardboard (laid at the bottom of each tire to keep the dirt from falling out), aluminum cans, and glass bottles are the the primary re-purposed materials used in earthships’ construction. Also, junk yard materials like metal sidings from discarded appliances or automobiles have also been used from time to time. On Earthship Biotecture’s (EB) humanitarian build projects in other parts of the world, where the trash make up is often different, other things have been used as well like plastic bottles and plastic bags (for insulation). The climate and environment of the location determine the earthship design type as well as the materials used. In terms of the natural and local materials, these would be things like the vigas, dirt, rocks, adobe plaster, mud bricks, sheep’s wool, coconut husk, bamboo, and seaweed. A bonus feature of using rammed earth, earthen berm, and adobe plaster is that they are also naturally fire resistant.
Re-purposing any waste is always a good thing of course because we do have a serious trash problem. Especially if it’s the type of trash that is very polluting and toxic to life like microplastics. But, much like sifting through the jumbled pile of mismatched clothes at a sale, there is no consistency in terms of quality and size of what you might find and so this can be very time consuming. You never know what or when you will find something you can or want to use. In fact the variation in the availability of the right sizes of tires is a feature of using them as building materials. The unconventional design of earthships, and use of re-purposed materials, also require some customization which adds to the time and skills requirement. Building with cans and glass bottle takes some learning and practice for sure. For tires, cans, and glass bottles, one can depend on there always being plenty of those around, especially in industrialized countries. But beyond that, it’s a hit or a miss.
So, it ends up being that earthships DO use quite a bit of conventional building materials. There are rebars, ply wood, cement to make concrete and plaster, PVC pipes for the plumbing, electrical wiring, EPDM rubber liners, 3–4 massive water cisterns per the full sized earthship types (though these can also be custom built with concrete), plastic and fabric liners, polyiso insulation (foam), pro panel metal sheets for the roof, glass panes for the inner and outer greenhouse, all the nails, screws and bolts, and more. A lot of these materials are not particularly sustainable nor eco-friendly. The price of construction materials have also increased significantly in the past few years; partly from the economic fall out of Covid. Hence the use of cans and bottles has the added benefit of reducing the amount of concrete needed — which is a cost saving.
There have also been some concerns raised about potential for “off gassing” as old tires degrade over time. However, once the tires are completely encased in dirt and plaster there is likely minimal health risk; pending further study. Rubber breaks down and releases toxic chemicals when discarded in open landfills and exposed to sunlight and the elements, but this is not taking place in the case of earthships. Considering what we’re already being exposed to in our conventional homes on a daily basis, the risks here with earthships are no worse.
2. Passive Solar Heating and Cooling
This aspect is likely one of the best feature of earthships’ design. The dirt pounded tire that forms the entire back, west, and east walls of an earthship, together with the earthen berm built up behind it, creates a thermal mass that acts like a giant heat storage battery. It absorbs heat from the sun through the south-facing (in the northern hemisphere) greenhouse during the daytime and releases the heat back into the space at night when the sun has gone down. The double greenhouse design helps to ensure that the temperature in the comfort zone (main living space) remains fairly constant at around 70F regardless of how cold the outside temperature gets. In the summer, when you are needing to cool the space, the 10" x 20–30 ft buried galvanized steel cooling tubes that run from the back tire wall and out the earthen berm is your A/C.
Since this is all passive heating and cooling, no external energy source is required to operate any machinery to drive these mechanisms. It’s 100%, manually operated, low tech. No burning of fuel is needed to generate heat. Some earthship owners have added a woodburner stove for either aesthetic reasons or in case of extreme cold. No electricity required to operate any A/C. No financial burden of bills for heating and cooling your home. Imagine how much this would help out low income folks struggling to pay their bills as we continue to face fuel shortages and rising energy costs! Two thumbs up!
3. Renewable Electricity and Battery Storage
Solar, coupled with battery storage, is the most typical renewable (RE) technology used in earthships, but they have also experimented with wind as well. What type of RE power source will make the most sense for you, in terms of cost and accessibility, depends on where in the world and what climate you are building your earthship. The great news is that RE technology is improving and becoming more affordable all the time.
Since heating and cooling are taken care of passively, the main electrical needs of an earthship are the lighting, hot water heating, kitchen appliances, washing machine, dryer, various pumps, TV, and any other technology that requires electrical power of some sort. The more things you have that need electrical power, the higher your demand will be. Some types of appliances are discouraged entirely due to being energy vampires. The amount of power you have depends on your battery storage capacity and type of power source. Solar can only charge up during the daylight hours; presuming it’s not too overcast. Wind could generate power any time of the day as long as there is wind. Regardless, you will likely have a finite amount of power at certain times of the day and will have to pick and choose what you want to use it for and when. Leaving the TV and the lights on all day long is probably not a good idea. Though living with limited power availability is not necessarily a bad thing because the way we have become accustomed to using energy in the home is completely unsustainable and wasteful.
Though I have reservations about the suite of RE technologies currently on the market and being promoted at the industry and policy levels, it’s the best alternative we’ve got for the time being vis a vis fossil fuel. There are negative human rights, social, and environmental impacts from the mining of raw materials — like cobalt, copper, and lithium —needed in the production of RE technologies. Hopefully, in the not too distant future, some big brain folks will develop new clean energy technologies that won’t require extracting and exploiting resources. Hydrogen? Nuclear fusion? Algae fuel? Anything is possible.
4. Water Harvesting
Water is Life. Literally. Water resources is one of the most critical issue that is being negatively impacted by the effects of climate change and our environmental destruction. Naturally, I was extremely excited when I learned that earthships use water collected from rain 4x before letting it return to the earth. Now THAT is efficient use of resource!
One issue here is that, for climates with low annual rainfall like Taos NM, they often are unable to harvest enough water from rainfall alone to meet the needs of a household. Sometimes they have to have water delivered. Perhaps in other climates with higher rainfalls this would not be an issue. At the same time, however, it doesn’t seem like they have really explored water resources management (like permaculture, for instance) on the outside of the earthship structure thus far.
In winter, when it often gets very cold, they have sometimes run into issues with snow and ice not melting effectively on the north side of the roof due to being more sheltered from the sun. They have incorporated solar heated glycol tubes to help melt the ice in the gutter. It’s unclear how effective this is not to mention the added cost of having to install another technology that can fail and require maintenance. This is one of those ongoing “trial and error” aspects of earthships’ design. Obviously, this would not be an issue in warmer climates.
5. Onsite Waste Water Treatment (Graywater & Blackwater)
Water used in the shower, bathroom sink, and washing machine are considered graywater and is run through the custom built graywater botanical cells (BCs) in the outer greenhouse. The graywater waters the plants in these BCs and in turn the BCs clean filter the graywater. Once the graywater reaches the farthest BC, the water is then pumped to be used to flush the toilet and any excess is recirculated back to the first BC.
Water from the kitchen sink and flushed toilet go straight to the buried septic tank outside the earthship. Overflow from the septic tank is directed into the blackwater BC and then leach field beyond.
Potentially, one could plant anything except for root vegetables and leafy greens type of edible plants in the blackwater BC. Flowering shrubs for pollinators and small trees would work well here. Unfortunately, the earthships we saw were either recently completed or no real effort had been made to grow anything substantial on the blackwater BC. We were not able to visit any of the private earthship properties at the The Greater World; for obvious reasons. They are private homes.
How well the wastewater treatment system works depends somewhat on proper earthship operation and maintenance such as ensuring that no toxic chemicals enter the drainage system, nothing that can obstruct the filtration process, regular cleaning and maintenance, and choice of plants and care. As Mike Reynolds explained to us, an earthship is like a machine that comes with an operation manual. So, proper care, maintenance, and operation is required for smooth functioning over time.
6. Food Production
It is certainly cool to see full banana and fig trees growing in an earthship greenhouse when it’s 20–30 F outside. But when you’re thinking about feeding a household of 4–5 people, you’re going to need way more than that.
How productive your indoor earthship food production is depends on a number of factors, including but not limited to:
- the size of your earthship;
- well planned and designed plant choices, positioning, and spacing according to the principles of permaculture and biomimicry; and,
- the willingness and competence of the human inhabitants to steward the healthy function of the “managed greenhouse poly-culture”.
Given the labeling of this design principle, one might assume that every plant in the outer greenhouse BCs can be for food production. However, the primary function of these BCs are for graywater filtration and so the plants here must serve this purpose first and foremost — especially for the plants selected for the BC where the graywater first enter the system. One of the first things they will tell you about living in an earthship is that all soaps and detergents must be biodegradable, eco-friendly, and non-toxic because of the contained waste water treatment system where the water is intended for food production plants. But even with biodegradable soaps and detergents, it is recommended that the plants in the first BC should be the hardiest type of plants (i.e. ones capable of tolerating and filtering higher concentration of contaminants) like wetland plants. As you move along the system into the second and third BCs, the water gets cleaner and cleaner and so different types of plants can be selected accordingly.
Other considerations for plant selection, besides food production, includes:
- companion plants (certain plants complement each other);
- medicinal properties;
- pests control;
- eventual height and width when fully matured (will create shade and/or compete with neighboring plants);
- indoor air purification & mental health benefits; and,
- aesthetics.
Of course not all the plants must be grown in the graywater BCs. You can add hanging pots and have standing box planters elsewhere in the outer greenhouse space, especially if you have one of the larger earthships with enough space. You can certainly also take advantage of your outdoor food production capacity as well like planting fruit trees on your blackwater BC and other edible plants elsewhere on your property; except for the leach field as that must remain untouched according to onsite waste water treatment regulations. In warmer climates with higher rainfall, your outdoor food production capacity is going to be much higher too.
Unlike potted house plants inside conventional homes, having graywater BCs inside that mimic healthy ecosystems’ function entails accepting all that comes along with it. Meaning: the bugs. The good helper ones of course. But if you’ve ever lived in hot tropical climates near ground level, there is no being 100% bug-free inside the house unless you are willing to use some seriously toxic pesticides that will probably be harmful to the human inhabitants as well. There will be critter friends like ants, little lizards, house flies, spiders, mosquitoes, cockroaches, and sometimes the occasional larger critters that sneak in. As long as it’s not at an infestation level, we get use to living alongside each other.
Conclusion
You are certainly not 100% self-sufficient and autonomous in every aspect of living in an earthship as far as I have seen at The Greater World. Folks are still supplementing with fuel for the home & vehicle, going to the grocery stores, and sometime purchasing water to fill up the cisterns. Perhaps in some other climates, where there is greater rainfall and one can grow a lot of food outdoors, one could achieve a greater degree of water security and food independence — even have chicken and other small farm animals. But maybe to be 100% self-sufficient is an unnatural goal in and of itself, and one that we should not be aiming for anyhow. Nature is, after all, a system that tend towards balanced and harmonious interdependence.
Earthship design has been primarily developed in the climate of Taos, NM — namely, high elevation dry desert. Even though EB has developed a few other earthship designs for tropical climates, there hasn’t been a lot of opportunity to really explore and innovate for other types of climate. There are a host of other types of off grid sustainable dwellings, using different materials and building techniques, being developed out there worth exploring. Not to mention existing traditional building techniques of the native inhabitants in any given locality that we can certainly draw from.
My biggest reservation about earthships, in its current iteration, is that they are costly, labor intensive, and require some specialized skills to build for the average person off the street who have lived their whole life in a modern society. Most of us have no construction skills nor studied civil engineering. We did not learn basic plumbing nor electrical work. Even if you hired a conventional construction crew, most of them will not be familiar with building earthships. It would not be easy to scale-up earthships in its current form without some sort of large scale investment programs to build the necessary capacity to be able to make something like earthships more widely accessible to the masses. Depending on the situation, there is certainly potential for adapting the earthship design as well choosing a la carte certain aspects— i.e. food production, water harvesting, or installing solar panels and batteries. We can also retrofit and improve the energy efficiency of conventional homes.
As Mike Reynolds described to us, an earthship is like a living machine that requires constant human interaction with it to maintain its functions. For instance, if you had an earthship and left it unoccupied months at a time, the plants will die because there is no one to shower, turn on the taps, or use the washing machine that would feed the graywater BCs.
Overall I believe earthships do work as a highly energy and water efficient sustainable dwelling. Naturally, there is still room for improvement and continual evolution just like anything else. Whatever drawbacks there are in the functionality of an earthship, they are no worse than those that currently exist with most conventionally built homes hooked up to the grid. Mike Reynolds and the EB team are definitely on to something here with their earthships.
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Read the other blogs in my Earthship Chronicles series:
Part I— Why I went to Earthship Academy
Part III — A Month in an Earthship
Part IV — Earthships and Beyond
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Resources:
Earthship Biotecture website ; Design Principles
Earthship Biotecture’s YouTube channel — tons of videos explaining how earthships are built & function
Garbage Warrior — 2011 documentary about Mike Reynolds & his earthships; http://www.garbagewarrior.com/
New Earthships capture more energy, water and food at lower cost — Kirsten Dirksen YT channel
How to build Off-Grid Earthship Homes with Trash! — Belinda Carr YT channel
Earthships — America’s Off-Grid Community — Off the Cuff YT channel
The Off Grid Guru YT channel — lots of good info. on this channel created by a guy who went through the EA himself and spent some time at the Greater World.
