|Image from Real Adventures.|
Since blogging in January about earth ship construction, we've been holding on to our empty glass bottles and collecting discarded tires from our neighbors. And today, we'll break ground on a small earth ship cottage.
An Earthship is a passive solar home made of natural and recycled materials. The structures are by design completely self-sufficient and in harmony with the environment.
|An earthship wall: glass bottles and mortar.|
Earthships are typically constructed from old tires, bottles, cans, adobe, stucco, and wood—in other words, a lot of materials that would otherwise end up in a landfill.
So how does it work? Here's the full run-down.
The term "earthship" was coined by Taos-based architect Mike Reynolds to describe his particular brand of environmentally sustainable architecture. As such, the phrase is virtually synonymous with the thermal mass, off-grid, earth-rammed tire and aluminum can-based "U-room" constructions that Reynolds has made famous on the Taos mesa. The rolling sea-green sage-covered Taos mesa which many earthships now populate easily becomes a metaphor for the ocean (an ironic one at that). One might speculate that this was part of what conspired to birth the phrase. The most solid origins of the term however are in the earthship's very character and philosophy. An earthship requires the much more active participation and alertness of its occupant in order for the dwelling to achieve optimal performance. In this regard, an earthship occupant is more of a pilot or sailboat captain than a neutral passenger. He or she must remain casually attentive to his changing environmental conditions in order to respond appropriately and derive peak levels of control and utility from his vessel.
The path of water in an Earthship:
- Water is caught from roof catchment systems and channeled via silt catches into cisterns.
- Cisterns gravity feed a DC pump and filter panels (WOM).
- A Pump and filter panel (WOM) pushes water into a pressure tank and conventional household water pressure is the result.
- The Toilet is separated from drainage system of all other household plumbing fixtures.
- Water is used in a conventional way such as bathing or washing dishes.
- Next, this water is then drained into linear biologically developed interior greywater treatment and containment systems.
The Water Organizing Module
Water from the city, cistern, your well, etc. can all be hooked up to the WOM. Automated systems can manage your water levels.
Filters clean the water for human consumption and use. Bottom Line: Your home has normal plumbing; your plumber sees what they are used to seeing.
Electricity: Earthships produce their own electricity with a prepackaged photovoltaic/wind power system. This energy is stored in batteries and supplied to your electrical outlets. Earthships can have multiple sources of power, all automated, including grid-intertie.
Use: Washing machines, computers, kitchen appliances, print machines, vacuums, etc. can be used normally. No electricity is required for heating & cooling.
Adjusting to Temperature changes isn’t as complicated as it sounds. The comfortable temperature range in any earthship is largely provided for by the natural thermal stability of the earth itself. Many amphibians & reptiles survive winters by burying themselves below the earth's frost line. Below the frost line, temperatures hover at a fairly stable 55-58 degrees. The earthship design takes advantage of this by being dug partially into the earth, or heavily earth-bermed along the outer walls, or both. Skylights provide the release of built up heat in warm climates, and shading for frost glazing can control the amount of solar energy coming in. The orientation of the "U-rooms" and angle of the front-facing glass also play key roles in how much heat is absorbed or dismissed by the dwelling. In extremely hot climates, U-rooms may be pointed away from the midday sun. Additional cooling can be provided for by a pipe run through the cool underground and into the earthship for an all-natural air conditioner.
Earthships are built just about everywhere on the planet. Differences in climate and orientation to the sun play a key role on the design requirements for optimizing earthship performance for a given location, but location itself has not proven to be particularly prohibitive for this type of off-grid dwelling. .
Typical Earthships are made out of earth rammed tires. An earthship of the kind made notable by Michael Reynolds uses earth-rammed automobile tires in "U" shaped room modules for the primary structural load-bearing walls, and a combination of cement and aluminum cans for interior, non-load-bearing walls. Front-facing glass is constructed using wood-framing and large standard sized sheets of glazing. Roofs are usually built with wood framing and sometimes vigas as well as aluminum or rubber sheeting as waterproofing.
Tire Odors? There is no verifiable information to date that suggests that off- gassing of tires occurs in an earthship.
10 Steps to building a simple Earthship
- On the bare earth, mark the outer walls in a circular or U shaped layout.
- Lay the first row of tires, shoulder to shoulder along the wall line.
- Using the dirt from the inside of the wall line, firmly pack the tires until they are solid bricks. The earth cliff on the inside would be excavated down to roughly three feet in depth.
- Stack the second row of tires, in a staggered layout, on top of the first, paying attention to keeping them level with each other. Continue this pattern until the walls have reached the desired height.
- Fill any voids with empty pop cans and/or glass bottles and cover the tire walls, inside and out, with mud adobe, cement or stucco to create a smooth finished surface.
- The roof can be domed shaped, formed from rebar that is wired or welded together then covered with chicken wire and cement. Other options would be log beams or even traditional trusses. A skylight/vent is included in the design to the rear of the structure to help regulate internal temperatures.
- The front of the structure is a sloped greenhouse wall built upon a low wall of earth rammed tires and includes a large planter box on the inside. The glazing is recycled sliding glass door panels or similar materials. The entry door is constructed at either end of the greenhouse hallway.
- Any interior walls are constructed of a cement and pop can matrix that is covered by an adobe finish. All the planter boxes are built the same way.
- The house systems include a rain water catchment cistern, a battery bank, solar panels, power inverter and a composting toilet. The kitchen wastewater is filtered via the greenhouse planters which grow fresh vegetables year round.
Finishing touches include tile or flagstone floors, glass bottle accent windows and wood inlays. Two story designs can include spiral staircases and just about any kind of custom design feature you can imagine.
The exposed surfaces on the outside of the structure are coated with a layer of cement, mud adobe or stucco as the climate demands. Most of the external tire walls are earth bermed and the roofing material is chosen to facilitate capture of rain water for use inside the house. Of course attention must be paid to things like drainage and choosing the best southern exposure for the greenhouse front of the dwelling, but otherwise it is a pretty simple design.