page_title: Earthship
section_title: Construction and design
hierarchical_section_title: Earthship / Construction and design
context_page_description: An Earthship is a brand of passive solar earth shelter that is made of both natural and upcycled materials such as earth-packed tires, pioneered by architect Michael Reynolds.
  Earthships are predicated upon the idea that there are six human needs which can be addressed through environmentally sustainable building design:
  Energy: Thermal and/or solar heating and cooling, solar and wind electricity
  Garbage Management: Reuse and recycling built into construction and daily living
  Sewage Treatment: Self-contained sewage treatment and water recycling
  Shelter: Building with natural and recycled materials
  Clean Water: Water harvesting and long term storage
  Food: In-home organic food production capability
  Earthship structures are intended to be "off-the-grid-ready" homes, with minimal reliance on public utilities and fossil fuels. They are constructed to use available natural resources, especially energy from the sun and rain water. They are designed with thermal mass construction and natural cross-ventilation to regulate indoor temperature, and the designs are intentionally uncomplicated and mainly single-story, so that people with little building knowledge can construct them.
context_section_description: The buildings are often horseshoe-shaped due to the difficulty of creating sharp 90 degree angles with rammed tires. In Reynolds's prototype at Taos, the opening of the horseshoe faces 10–15 degrees east of south to maximize natural light and solar-gain during the winter months, with windows on sun-facing walls admitting light and heat.
  The book, Earthship I, describes how to find the best angle depending on the building's geospatial location. The thick and dense walls provide thermal mass that naturally regulates the interior temperature during both cold and hot outside temperatures. The outer walls in the majority of Earthships are made of earth-rammed tires, but any dense material with a potential to store heat, such as concrete, adobe, earth bags, or stone, could in principle be used to create a building similar to an Earthship. The tire walls are staggered like traditional brick work, and often have "concrete half blocks" every other course, to equal the length of the staggered tire below. In an effort to cut down the use of concrete even further, they also use "squishies" - tires rammed in between a tight space to even out the course or to compensate for varying tire size.
  The rammed earth tires of an Earthship are assembled by teams of two people. One person shovels dirt and places it into the tire one scoop at a time. The other person, who stands on the tire, uses a sledgehammer to pack the dirt in while moving in a circle around the tire to keep the dirt even and to avoid warping the tire. Rammed earth tires can weigh up to 300 pounds, so they are typically filled in place. Because the tire is full of soil, it does not burn when exposed to fire.  In colder climates, extra insulation is added on the outside of the tire walls. It uses modern technologies such as solar cells, solar collectors and water filtering systems.
  On top of the tire walls are either "can and concrete bond beams" made of recycled cans joined by concrete, or wooden bond beams with wooden shoes. These are attached to the tire walls using concrete anchors, poured blocks of concrete inside the top tires. Wooden shimming blocks placed on top of the wooden bond beam make up the wooden shoes. The wooden bond beam consists of two layers of lumber bolted on to the concrete anchors. Re-bar is used to "nail" the wooden shoes to the wooden bond beam.
  Internal, non-load-bearing walls are often made of a honeycomb of recycled cans joined by concrete; these are nicknamed tin can walls. These walls are usually thickly plastered with adobe, and resemble traditional adobe walls when finished.
  The roof is made using trusses, or wooden support beams called vigas, that rest on the wooden shoes or the tin can walls placed on the bond beams. The roof as well as the north, east and west facing walls are heavily insulated to reduce heat loss.
caption: Most earthship structures are earth-sheltered buildings with a large series of windows and used tires