When you consider that around 300 million tires are discarded every year in the United States alone, coming up with inventive ways of recycling these into new products and projects is vital to ensure they don’t end up in a landfill. One innovative use that has been embraced in the last few years is the construction of tire homes, with their most well-known incarnation as “Earthships”.
What Are Tire Homes?
Tires homes are created by packing tires full of earth, then stacking them as you would bricks, before being clad with compacted earth to essentially create a rammed earth home. In addition to utilizing an otherwise waste product, they are designed to maximize energy efficiency, reducing heat penetration during the summer and storing warmth during the colder months.
Tire homes as Earthships are intended to be off-the-grid, with little to no reliance on public energy sources and fossil fuels. They address the six basic principles that are essential for sustainable housing design and lifestyle:
- Thermal/solar heating and cooling
- Solar and wind electricity
- Contained sewage treatment
- Natural and recycled building materials
- Water harvesting
- Food production
Constructed from locally-sourced resources, they are designed to take advantage of the energy from the sun, with natural cross ventilation to help regulate the indoor temperature. The simple design allows even those with little building knowledge to construct themselves, creating thick, dense tire walls that are staggered like regular bricks.
Bond beams made from recycled cans joined by concrete or wood are attached using concrete anchors, while internal walls are often constructed using recycled cans which are then plastered with adobe. Tire home roofs are made using trusses or wooden support beams and usually heavily insulated to reduce heat loss.
The result is a horseshoe shaped structure (as it’s difficult to create 90 degree angles with rammed earth tires), with its opening typically facing toward the Equator to maximize natural light and heat gain during the cold winter months. Large windows across this “front” of the building allow for optimum solar exposure and many modern designs include a double greenhouse here. An internal glass wall separates a light-filled walkway from an exterior greenhouse which is used to grow food and other plants.
Earthships collect and store their own energy, predominantly from the sun and wind, with solar panels and wind turbines installed to capture electricity in deep-cycle batteries. A Power Organizing Module (POW) is provided by Earthship Biotecture to be attached to an interior wall and wired so that it can be used to run all household appliances.
The combination of tire walls and compacted earth use the properties of thermal mass to soak up heat during the day and radiate it at night, ensuring the interior climate remains comfortable without the need for heating or cooling appliances. Some tire homes are also sunken into the earth to draw on the benefits of earth-sheltering which further reduces the temperature fluctuations of the exterior air. The interior is naturally ventilated using a convection model, with hot air rising and blowing out through vented windows, creating a steady airflow as cool air comes in.
Rather than the tires being a serious fire risk (as they are on their own), they are sealed within thick walls so that they cannot react with oxygen. The plaster adds fire resistance to the building and tire homes usually meet (or exceed) local fire regulations.
Water is collected on the roof and funneled into a cistern. This feeds a water organization module to filter out bacteria and contaminants. This is then pushed into a pressure tank where it can be utilized for common household activity, except toilet flushing which is done with recycled grey water. This is sourced from sinks and showers, then filtered through a rubber-lined botanical cell for oxygenation and filtering before use. Water used to flush toilets is then considered “black water” and septic tanks using anaerobic digestion naturally separate the solid waste before it is used to water the garden.
The idea behind Earthships is not just sustainable construction and recycling used tires, but about creating a house that is largely self-sustaining, working in harmony with the surrounding environment.
On average, a 2,000 square foot tire home would use around 1,000 tires that would otherwise end up as scrap. In addition to rammed-earth tire houses, tire-bale homes have also been created, using significantly more tires. Tire-bale homes use square bricks, each of which contain approximately 100 compressed tires and weigh in at around 2,000 pounds. These are then stacked to create an exterior house frame and finished with a layer of plaster or stucco.
Who developed them and why?
Architect Michael Reynolds has been credited with the first tire-built Earthships, building his “Thumb House” in the early 1970s and developing the concept further throughout the decade. He had three things he wanted to achieve through this innovative construction:
- Make use of locally sourced and recycled materials wherever possible;
- Be independent from the grid and rely on natural energy sources;
- Built by a person with no specialized construction skills.
Over time, these building ideas evolved into the horseshoe shaped Earthships seen today. “Earthship” is now a trademarked name and design of Michael Reynolds who runs his Earthship Biotecture company from Taos, New Mexico.
Where Are They Used?
Since Mike Reynolds’ first tire home back in the early 1970s, Earthships have been built across the world, from a school in Sierra Leone to a recycling center in Khayelitsha, South Africa and a visitor’s center in Ushuaia, Argentina. Despite challenges in obtaining planning permission, Earthships have been built across Europe, including Portugal, Spain, France, Belgium, the United Kingdom, Sweden, Denmark, Germany, Estonia and Czech Republic, with the first official Earthship district created in Olst in the Netherlands containing 23 tire homes.
For those interested in the process of building a tire home, together with the difficulties of obtaining permits to build in such an unconventional, off-the-grid manner, the film “Garbage Warrior” follows Mike Reynolds as he aims to do just that.
Tire Homes in the Developing World
Tire homes and Earthships take significant time to build and are designed to be permanent dwellings. This means that their use for temporary disaster relief housing in the immediate weeks following natural catastrophes or wars is not practical. But as the Haiti Earthship Project has shown, tire homes are one way that people in the developing world can create permanent and sustainable housing, without the need for imported materials.
The project aims to put “housing back into the hands of the people”, free from corporations, politics and largely independent of oil. The Earthship model that has evolved over the last four decades in Europe and the United States is being applied in Haiti’s developing world situation and based on local requirements, ensuring people can replicate these houses and building techniques well into the future.