What is an Earthship, and why should I give a shit?

So, what is an Earthship?

An Earthship is a house.

It's a house that requires no power to run, which produces food, heats and cools itself, collects rain water for drinking water, and treats the sewage that is the byproduct of human use of that water and food.  In this way, above and beyond merely being houses, Earthships are highly engineered passive human-sustaining habitats.

But houses already exist! All of these problems already have solutions, most or all of which are still accessible! Why does this matter at all?

Because Earthships can be made to do this in any environment on earth, using locally sourced materials that are normally considered garbage, such as discarded cans, bottles, and tires. Thus, they not only represent an emerging technology set that can and will outcompete our current house building technology, they are a sustainable solution, and one that is deliverable as humanitarian aid, for maximum benefit, with minimum investment.

Earthships are beautiul state-of-the-art homes which require little or no infrastructure and have little or no overhead. Made of garbage.

So, the above portion is largely rhetoric, and not actionable or useful, so here I'll describe a 'basic' earthship and list examples of this set of technology in action and explain some of the points about it.

What does an earthship look like?  Any house can look like an earthship, but there is a 'classic' model that most draw elements from.  Earthships are always oriented to use the sun, and so in the northern hemisphere face south, and in the southern, north.  The sun-facing sides are usually built as green houses with solid stone or rammed earth floors to catch the heat from the sun in a deliberately warmed portion of the house. At the top of these green houses are vent windows that allow hot air to blow out.  Behind the greenhouse portion is the house proper- these are typically long linear structures built into the side of a hill, with tire walls forming the outer boundary and smaller dividing walls inside to allocate the space into rooms.  Over the top is a typically shallowly sloped roof, also typically covered in sheet metal painted a single coherent color (as a cheap, efficient, durable, light, and non-contaminating way to funnel the rain water into the collection system), which are typically on the north (in the northern hemisphere) side of the house, but which can be located just about anywhere. Typically, to keep them out of sight and mind, the water tanks that the rain water is stored in are under ground, although this is not always the case.

The Waybee earthship in Taos, NM, draws on the local Spanish and Adobe influences.

Beyond this, there aren't any real features to conclusively identify a building as an earthship or not. I say, your house can probably be turned into one, and figuring out how to make that happen is one direction of my research into these.

Tire walls being built.

Why tires?  Because tires are steel-reinforced hoops of rubber casing that never decays, or for all practical purposes will never decay in the span of a human life.  Because of this, they are a special challenge for our waste disposal infrastructure, or else new uses need to be found for them.

In earthships, tires are used to make large rammed-earth 'bricks' to build heavy foundations and structural components.  A piece of cardboard is put in the tire to initially keep the dirt from falling out of the bottom, and then the tire is filled with dirt.  When it is filled as full as can be, a sledge hammer is used to pack the dirt into the walls of the tire, and more dirt is added and then packed until the tire wall bulges on all sides equally. At this point, the pressure of the tire squeezing the dirt is sufficient to render it a single solid building block- for a normal (26 inch) tire, these will typically weigh 300 to 500 pounds.

A field of discarded tires, Kuwait.

Why is this good?  First, tires are cheap, even free- and in many cases, you can even make money by charging some small amount for people to dispose of them with you, although this depends on the environment and part of the world you find yourself in.  Second, because they are so wide, they do not legally require a concrete slab foundation under them, and so they can be used as a building material and meet building codes, even if some more antiquated building code systems may not have specific named provisions for these (which will change, eventually).  Third, because these tires and dirt together have a lot of mass crammed very densely together, they absorb and retain heat very well- an effect which is capitalized on to passively drive convective heating and cooling to provide climate control in earthships- which, admittedly, can be done many ways with many materials besides tires, but of the available set of materials used in this sort of construction, tires represent an extremely cheap, convenient, accessible, and useful way to implement this.

One final note about tires: I can't make extravagant claims yet, but I am examining the potential of rammed earth tires as structural components for large scale civil engineering applications, and the future here seems bright. I suspect properly buttressed tire structures that use rebar to distribute load across all of the structure could see tire arches (as in, weight-bearing bridges made from tires), sky scrapers, dams and levies, and so on. There are great possibilities.

Bottles... as bricks? WTF?  Well, first, that needs to be qalified- no, you don't just slap some concrete on a bottle and call it a brick. What actually happens to make these is that the neck and shoulder of two matching bottles are cut off, the resulting 'cups' of the bottom of the bottle are washed and dried, and then they are put top-to-top and the seam between them is wrapped in duct tape, creating a hollow cylindrical 'brick'.

The way these 'bottle bricks' get used is NOT as a structural component, but rather as a weight-reducing component.  By adding a bottle to a cob, adobe, or cement wall, you are reducing the amount of mass required to make that wall, and reducing the weight of the wall at the same time.  By using bottle bricks to do this, you can arrange them in patterns, constellations, and even make what look like mosaics of stained glass.   The effect of sunlight on a brown bottle such as a beer bottle is to render them a red-orange; green glass becomes a more brilliant shade of emerald. And so, even though these are sourced from discarded materials, they result is an easy to make and aesthetically pleasing little jewel of a window that can let additional light into your house while making it lighter and more structurally sound.  These are particularly popular in bathrooms, where more light but less outside visibility is usually desirable.

Plastic bottle bricks being laid in Kenya.

Then what about can walls? what about plastic bottles?  These are essentially the same idea- reducing the total input of building material, reducing the total weight of the wall- and by dint of using disposable garbage to take up the space that various sorts of mud might otherwise have to occupy. Aluminium drink cans, particularly, tend to have solid uniform bottoms and tops, and these make for very good building materials that it is possible to make very interesting geometric patterns, while plastic bottles have the advantage of being very easy to work with using even simply a knife, and some of the more environmentally conscious earthshippers have taken to filling these plastic bottles with additional volumes of plastic garbage to use it up, dispose of it, and create denser filling material all in one go.

Collecting Rainwater is the next concept to understand. In an Earthship, rain water is harvested via the gutters funnelling the rain that lands on the roof into a filtration and storage system that stores a finite portion of all rain that lands on the house.  If the system fills to capacity, it simply does not store any more and the rain flows off the house and over the collection onto the ground and into the water table as it normally would, without interruption.

Once rain water is collected, there are four primary uses for it.  First, it is filtered and made available to the primary treated water plumbing of the house, to be available for drinking, cooking, etc.  Second, the water that goes down the drain from this is fed into the green house at the south side of the house.  Third, once it has fed the botanical cell there (which removes the solids and organic compounds from the water), it is used as the water to flush the toilet for the house septic system. Fourth, once it has been flushed, it is put into a septic digester to first sterilize and break the amonia compounds down into nitrates and nitrites, and then this resulting nutrient mixture is pumped into a botanical cell outside the house, where it can be used to drive landscaping or can be used for further gardening, from a contained cell that will not pollute the water table or lose moisture content too rapidly if the water table is too low, such as in especially arid regions.

Food Production, and what the heck is a "Botanical Cell"?  So, in the green house, the premise is that a deliberately engineered human ecosystem can passively do the work that would otherwise require machines, investment, and human labor: they can clean shit out of water, for given values of 'clean' and 'shit'.

What does this mean? It means that, in the area that is the entrance to these houses, no matter what the climate or weather might be outside, there is usually a garden that is established around the time the house is built which continues to produce indefinitely.  I have seen banana trees, fig trees, tomatoes, strawberries, all manners of herb and spice, and many other things grown in such settings.  Because the green house is the portion of the house which collects and accumulates heat to drive the passive heating (and cooling) systems, keeping plants- even tropical plants- at temperatures which they will produce fruit requires no action to be taken after planting.  Since it is an indoor environment, there isn't weeding to do; as long as there is somebody at the location occasionally using the sink and flushing the toilet, there will be water delivered to these botanical cells- no manual watering is ever required.

The outdoor botanical cells are essentially the same idea, but are separated because the source of the water is from the black water / septic system.  It isn't that there is no capacity to clean this to the point that it couldn't be used indoors, but as a way of meeting code, preventing problems associated with clogs and backups, even though these work essentially the same way, the one inside the earth ship is usually just cleaning soap and tooth paste out of the water, rather than less savory components.

This is the tip of a very large iceberg.

To illustrate what urban food production looks like, lets take tomato plants. In an environment that supports them in doing so, they will grow indefinitely. A well established year-old tomato plant, producing beef steak tomatoes, will produce them in bunches of what look, at first glance, exactly like cherry tomato bunches, with each tomato being 10 times the size of a cherry tomato.  Here's one that's 50 weeks old (two weeks short of a year), 24 feet long, still producing fruit, and still growing, pointed out about halfway through this video. Check it out.

Further Data:

• Garbage Warrior, a documentary that was made to comprehensively explain this topic by the actual Earthship people. On Yootoob here.
• A house tour, to give some context to what a conventional function-first earthship would look something like 
• Here is an excellent look at some of the features, design principles, and operating constraints of the building methods described here.