Earthship

South and East view of Earthship passive solar home

An earthship is a type of passive solar house made of natural and recycled materials. Designed and marketed by Earthship Biotecture of Taos, New Mexico, the homes are primarily constructed to work as autonomous buildings and are generally made of earth-filled tires, using thermal mass construction to naturally regulate indoor temperature. They are usually passively ventilated by cross ventilation assisted by thermal draught (Stack effect). Earthships are generally off-the-grid homes, minimizing their reliance on public utilities and fossil fuels. Earthships are built to utilize the available local resources, especially energy from the sun. For example, windows on sun-facing walls admit lighting and heating, and the buildings are often horseshoe-shaped to maximize natural light and solar-gain during winter months. The thick, dense inner walls provide thermal mass that naturally regulates the interior temperature during both cold and hot outside temperatures.

Internal, non-load-bearing walls are often made of a honeycomb of recycled cans joined by concrete and are referred to as tin can walls. These walls are usually thickly plastered with stucco.

The roof of an Earthship is heavily insulated – often with two layers of four inch poly-iso insulation – for energy efficiency.

History

Michael Reynolds' first building, the Thumb House. Built in the early 1970s, it incorporated designs found in later Earthships

The Earthship as it exists today, began to take shape in the 1970s. Mike Reynolds, founder of Earthship Biotecture, a company that specializes in designing and building Earthships, wanted to create a home that would do three things; first, it would be sustainable architecture, using material indigenous to the entire planet as well as recycled materials wherever possible. Second, the homes would rely on natural energy sources and be independent from the "grid", therefore being less susceptible to natural disasters and free from the electrical and water lines that Reynolds considered unsightly and wasteful. Finally, it would be economically feasible for the average person with no specialized construction skills to be able to create.

A building being built of cans in the 1970s

The design used with most earthships. A large series of windows and the use of tires characterize the earthsheltered building

Eventually, Reynolds' vision took the form of the common U-shaped earth-filled tire homes seen today. As a concept, the Earthship was not limited to tires – any dense material with a potential for thermal mass, such as concrete, adobe, dirtbags, or stone could theoretically be used to create a building similar to an Earthship. However, the earth-rammed tire is part of the definition of an Earthship.

Unlike many other materials, rammed-earth tires are easily accessible to the average person. Scrap tires are plentiful around the world and easy to come by; there are an estimated 2 billion tires throughout the United States. As of 1996, as many as 253 million scrap tires were being generated each year in the United States, with 70% being reclaimed by the scrap tire market (leaving perhaps 75 million scrap tires available for reuse as whole tires). In addition to being readily available, the method by which scrap tires are converted into usable "bricks" (the ramming of the earth) is simple and affordable.

The earth-rammed tires of an Earthship are usually assembled by teams of two people working together as part of a larger construction team. One member of the two person team shovels dirt, which usually comes from the building site, placing it into the tire one scoop at a time. The second member, who stands on the tire, uses a sledge hammer to pack the dirt in. The second person moves in a circle around the tire to keep the dirt even and avoid warping the tire. These rammed earth tires in an Earthship are made in place because, when properly made, they weigh as much as 300 pounds and can be very difficult to relocate.

Additional benefits of the rammed earth tire are its great load-bearing capacity and its resistance to fire.

A fully rammed tire, which is about 2 feet 8 inches wide, is massive enough to surpass conventional requirements for structural load distribution to the earth. Because the tire is full of soil, it does not burn when exposed to fire. In 1996 after a fire swept through many conventional homes in New Mexico, an Earthship discovered in the aftermath was relatively unharmed. Only the south-facing wall and the roof had burned away, compared to the total destruction of the conventional homes.

Currently, Earthships are in use in almost every state in the United States, as well as many countries in Europe. The use of insulation on the outside of tire walls, which was not common in early designs, is improving the viability of Earthships in every climate without compromising their durability. Earthships are continually being built by Earthship Biotecture around the world. Their popularity and use of inexpensive materials has inspired many to build their own homes as well.

Systems

The Earthship was designed as a structure that would be free of the constraints of centralized utilities, which most modern shelters rely on. Earthships must be able to create their own utilities, and to utilize readily available sustainable materials. In order to be entirely self-sufficient, the Earthship needs to be able to handle the three systems of water, electricity, and climate.

Water

Collection

A domestic rainwater harvesting system

Earthships are designed to catch and use water from the local environment without bringing in water from a centralized source. Water used in an Earthship is harvested from rain, snow, and condensation. As water collects on the roof, it is channeled through a silt-catching device and into a cistern. The cisterns are positioned so they gravity-feed a WOM (water organization module) that filters out bacteria and contaminants and makes it suitable for drinking. The WOM consists of filters and a DC-pump that are screwed into a panel. Water is then pushed into a conventional pressure tank to create common household water pressure.

Water collected in this fashion is used for every household activity except flushing toilets. The water used for flushing toilets has been used at least once already: frequently it is filtered waste-water from sinks and showers, and described as "Greywater".

Greywater

Greywater, used water that is unsuitable for drinking, is used within the Earthship for a multitude of purposes. First, before the greywater can be reused, it is channeled through a grease and particle filter/digester and into a 30"-60" deep rubber-lined botanical cell, a miniature living machine, within the Earthship. With imbedded plants, this filter also potentially can be used to produce food (for example, by using a fruit tree). Oxygenation, filtration, transpiration, and bacteria-encounter all take place within the cell and help to cleanse the water (Reynolds 2000). Within the botanical cell, filtration is achieved by passing the water through a mixture of gravel and plant roots. Because of the nature of plants, oxygen is added to the water as it filters, while nitrogen and phosphate is removed. Note that plant root cells do not produce oxygen but consume it; only the leaves of plants produce oxygen. Water taken up through the plants and transpired at their tops helps to humidify the air. In the cell, bacteria will naturally grow and help to cleanse the water.

Water from the low end of the botanical cell is then directed through a peat-moss filter and collected in a reservoir or well. This reclaimed water is then passed once more through a greywater board and used to flush conventional toilets.

Often, greywater made at earthships is not polluted enough to justify treatment (its "pollution" being usually just soap, which is often not environmentally damaging). At earthships, plants are placed at outlets of fixtures to regain the water and the nutrients lost (e.g. from the soaps). Usually, a single plant is placed directly in front of the pipe, but mini drain-fields are also sometimes used. The pipe is made large enough (5,08 cm) so that the formation of underground gas (from the greywater) is avoided. This is done with kitchen and bathroom sinks, and even showers, washing machines, and dishwashing machines. The plants are usually placed indoors with the sinks and outdoors with the washing/dishwashing machines and shower (to avoid indoor "floods"). Also, with the latter, larger drain-fields are used instead of a mere plant being placed before an outlet.

Black water

The water system with integrated flush toilet, as used in most earthships

Black water, water that has been used in a toilet, was usually not created within many of the earliest earthships as the use of conventional toilets was discouraged. Instead, in the early days composting toilets were advocated, which use no water at all. However, with the new greywater treatment system design (as used in Nautilus and Helios) created by Michael Reynolds, flush toilets have now found a place in the earthship and the general water system has been redesigned according to the new "6-step process".

Now, when the newly included flush-toilets are used, blackwater is not reused within the Earthship. Instead, blackwater is sent to a solar-enhanced septic tank with leach-field and planter cells (the whole being often referred to as the "incubator"). The solar-enhanced septic tank is a regular septic tank which is heated by the sun and glazed with an equator-facing window. The incubator stores the sun's heat in its concrete mass, and is insulated, to help the anaerobic process. Water from the incubator is channeled out to an exterior leach field and then to landscaping "planter cells" (spaces surrounded by concrete in which plants have been put). The cells are similar to the botanical cell used in greywater treatment and are usually placed just before and under the windows of the earthship.

In cases where it is not possible to use flush-toilets operating on water, dry solar toilets are now advocated, instead of regular composting toilets. If this is the case, obviously no black water is formed and the use of an incubator is thus (usually) not necessary. Instead, regular "planters" (plants used for sucking up water/nutrients) are then used. When using regular planters as well, no chemical soaps or detergents can be used.

The space where the WOM (water organization module), graywater pump panel, pressure tank, (first set of) batteries, and POM (power organising module) are stored is in a small room referred to as the "systems package".

Electricity

A PV-solar system

Earthships are designed to collect and store their own energy from a variety of sources. The majority of electrical energy is harvested from the sun and wind. Photovoltaic panels and windturbines located on or near the Earthship generate DC energy that is then stored in several types of deep-cycle batteries. The space in which the batteries are kept is usually a special, purpose-built room placed on the roof. Additional energy, if required, can be obtained from gasoline-powered generators or by integrating with the city grid.

In an Earthship, a Power Organizing Module is used to take stored energy from batteries and invert it for AC use. The Power Organizing Module is a prefabricated system provided by Earthship Biotecture that is simply attached to a wall on the interior of the Earthship and wired in a conventional manner. It includes the necessary equipment such as circuit breakers and converters. The energy run through the Power Organizing Module can be used to run any house-hold appliance including washing machines, computers, kitchen appliances, print machines, and vacuums. Ideally, none of the electrical energy in an Earthship is used for heating or cooling.

Climate

The interior climate of an Earthship is stabilized and made comfortable by taking advantage of many phenomena. Mainly, the Earthship tries to take advantage of the properties of thermal mass and passive solar heating and cooling. Examples are large front windows with integrated shades, trombe walls and other technologies such as skylights or Steve Baer's "Track Rack" solar trackers (dualling as an energy generation device and passive solar source).

The load-bearing walls of an Earthship, which are made from steel-belted tires rammed with earth, serve two purposes. First, they hold up the roof, and second, they provide a dense thermal mass that will soak up heat during the day and radiate heat during the night, keeping the interior climate relatively comfortable all day.

In addition to high thermal mass, some Earthships may be earth-sheltered. The benefits of earth-sheltering are twofold because it adds to the thermal mass and, if the Earthship is buried deep enough, allows the structure to take advantage of the Earth's stable temperature.

The Earthship is designed in such a way that the sun provides heating, ventilation, and lighting. To take advantage of the sun, an Earthship is positioned so that its principal wall, which is nonstructural and made mostly of glass sheets, faces directly towards the equator. This positioning allows for optimum solar exposure.

To allow the sun to heat the mass of the Earthship, the solar-oriented wall is angled so that it is perpendicular to light from the winter sun. This allows for maximum exposure in the winter, when heat is wanted, and lesser exposure in the summer, when heat is to be avoided. Some Earthships, especially those built in colder climates, use insulated shading on the solar-orientated wall to reduce heat loss during the night (Reynolds 2000).

Natural ventilation

Natural convection cooling an Earthship

The earthships usually use their own natural ventilation system. It consists of cold(er) air coming in from a front ("hopper") window, especially made for this purpose and flowing out through (one of) the skylights that are placed on the earthship. As the hot air rises, the system creates a steady airflow - of cooler air coming in, and warmer air blowing out.

Heating problems

Earthships rely on a balance between the solar heat gain and the ability of the tire walls and subsoil to transport and store heat. The design intends to require little if any auxiliary heat. Some earthships have suffered from overheating and some from overcooling.

Some earthships appear to have serious problems with heat loss. In these cases heat appears to be leaking into the ground constantly during the heating season and being lost. This situation may have arisen from the mistaken belief that ground-coupled structures (building in thermal contact with the ground) do not require insulation. The situation may also be due to large climatic differences between the sunny, arid, and warm Southwest (of the USA) where earthships were first built and the cloudier, cooler, and wetter climates where some are now being built. Malcolm Wells, an architect and authority on earth-sheltered design, recommends an imperial R-value 10 insulation between deep soils and heated spaces. Wells's insulation recommendations increase as the depth of the soil decreases.

In very limited and specific situations, uncommon during the heating season, thermal mass can marginally increase the apparent R-value of a building assembly such as a wall. Generally speaking thermal mass and R-value are distinct thermodynamic properties and should not be equated. Thermal performance problems apparently seen in some earthship designs may have occurred because of thermal mass being erroneously equated to R-value. The imperial R-value of soil is about 1 per foot.

Potential advantages

• Having an earth-bermed home with windows facing the sun is a good idea in any climate where heating is required.
• Collecting rainwater that falls on the roof reduces the runoff impact of the building and may reduce water and even sewer service fees.
• Having a combination of photovoltaic cells and wind generation is a prudent way to provide electricity in many situations.
• Using curved modules as horizontal arches to resist earth loads is a sound structural design.
• On-site processing of runoff water, grey water, and black water using plant beds reduces the environmental impact of the building.
• Rubber tires make a wind- and puncture- resistant wall. They may be safe from outgassing when plastered semi-airtight.
• Rubber tires are usually free and it may be possible to be paid to take them. It also is beneficial to keep them out of landfills or prevent them from being illegally burnt.
• Potential to eliminate utility bills.
• The structure is highly moldable to different aesthetic tastes.

Potential Disadvantages

• Aesthetics are not universally appreciated.

Europe

Brighton Earthship, UK

In 2000, Michael Reynolds and his team came to build the first residential earthship in Boingt (Belgium). While water, power module, solar panels and the team were on their way to Europe, the mayor of Boingt put his veto on the building permit. So Josephine Overeem, the woman who wanted to build the earthship, and Michael Reynolds decided to do a demonstration model in her back yard at her residence in Strombeek (Belgium). CLEVEL, invited Reynolds from Belgium to Brighton in the UK, and orchestrated plans for the earthship in Brighton, started in 2003. This was the beginning of a series of trips made by Reynolds and the construction of earthships in the UK, France and the Netherlands.

In 2004, the very first Earthship in the UK was opened at Kinghorn Loch in Fife, Scotland. It was built by volunteers of the SCI charity. In 2005, the first earthship in England was established in Stanmer Park, Brighton with the Low Carbon Trust.

In 2007, CLEVEL and Earthship Biotecture obtained full planning permission to build on a valuable development site overlooking the Brighton Marina in the UK. The application followed a successful six-month feasibility study, orchestrated by Daren Howarth, Kevan Trott and Michael Reynolds and funded by the UK Environment Agency and the Energy Savings Trust. The successful application was for sixteen one, two, and three-bedroom earthship homes on this site. The homes are all designed according to basic earthship principles developed in the United States and adapted to the UK. 15,000 tires will be recycled to construct these homes (the UK burns approximately 40 million tires each year). The plans include the enhancement of habitats on the site for lizards that already live there, which is the reasoning behind entitling the project "The Lizard". This would have been the first development of its kind in Europe, and successful development in Brighton may help to pave the way for similar projects around the UK and other places.

The first official Earthship home in mainland Europe with official planning permission approval was built in a small French village called Ger. The home, which is owned by Kevan and Gillian Trott, was built in April 2007 by Kevan, Mike Reynolds and an Earthship Crew from Taos. The design was modified for a European climate and is seen as the first of many for the European arena. It is currently used as a holiday home for eco-tourists.

Further adaptation to the European context was undertaken by Daren Howarth and Adrianne Nortje in Brittany, France. They obtained full planning permission in 2007 and finished the Brittany Groundhouse as their own home during 2009. The build experience and learning is elegantly captured in the UK Grand Designs series and in their book.

Meanwhile earthships have been built or are being built in Portugal, Spain, France, Belgium, The Netherlands, United Kingdom, Sweden, Estonia and Czech Republic. A good overview of the earthships built in Europe can be found on the web page of European Earthship Builder United, together with information on earthships being built. A good chronological overview on the earthships built in Europe by Michael Reynolds can be found in the article 'Europe'.

The first official earthship district (23 earthships) in Europe is currently being developed in Olst (the Netherlands). Building will start in spring 2012. In Belgium, 1 earthship hybrid is also being built, intended as demonstration buildings. Since it is illegal to use tires in Belgium (for risk of leaking toxic metals like lead and zinc), The project uses sandbags to build their earthship instead.

The Earthships built in Europe by Michael Reynolds aren't always performing as promised and some show problems with moist and mould. Some research into performance was done by the University of Brighton on the Brighton Earthship. Further research to adapting all but southern parts of European climate are definitely needed.

Africa

The first earthship in South Africa was built by Angel and Yvonne Kamp from 1996 to 1998. They rammed a total of 1,500 tires for the walls. The earthship, near Hermanus, is located in a 60 hectare private nature reserve which is part of a 500000 hectare area enclosed in a game fence and borders the Walker Bay Nature Reserve. The second earthship in South Africa is a recycling centre in Khayelitsha run as a swop shop concept. The centre was finished in December 2010.

Two other projects in development in South Africa are a combined bed and breakfast and information and training centre in Orania and a residential house in Swaziland.

Argentina

NaveTierra MDQ is a Mar del Plata-based project activating people and resources to build a demonstration NaveTierra (Spanish preferred contraction for Earthship). Until land for the project is acquired, knowledge is developed and put to work towards assembling the puzzle at the Estación Permacultural (Permacultural Station).

The film

There is a film titled Garbage Warrior about Earthships and Reynolds' struggle with the law.

Gallery

• 
  Earthship inside greenhouse.
• 
  E.V.E project under construction.
• 
  Inside Earthship visitors centers.
• 
  An Earthship interacts with the elements as part of the ecosystem.
• 
  Vaulted Earthship entrance.
• 
  Front face of a Global model Earthship.
• 
  Earthships are made of earth-rammed tires, cement, steel, bottles and cans.
• 
  Bottle walls are used in earthships such as this earthship bathroom, located in Phoenix Earthship, Taos, NM, USA.
• 
  Interior of the Solaria Earthship with sun coming in from the south facing windows (Taos, New Mexico)

See also

• Friedensreich Hundertwasser
• Geothermal
• Hurricane-proof building
• Permaculture
• Repurposing
• Spaceship Earth

References

• Hewitt, M. and Telfer, K. (2007). Earthships: building a zero carbon future for homes. ISBN 978-1-86081-972-8
• Klippel, James H. http://www.garrellassociates.com/EcoDesign.html, green page
• Reynolds, Mike. (2000). Comfort In Any Climate, Taos: Solar Survival P. ISBN 0-9626767-4-8
• Howarth, D. & Nortje, A. (2010). "Groundhouse Build & Cook". ISBN 978-0-9566947-0-6

Further reading

• Schirber, Michael. "Making Earthships Mainstream" on Going Green at msnbc.com, November 12, 2007.
• Raets, W.J.L., "Flagship Design Guides - General - Pre-Building and Design", June 15, 2012

External links

• Official website
• Earthship Europe
• Earthship Belgium