Earthship residence is really down to earth
By Stan Jones and Pattie Frost Jones on 03/16/2006
The Earthship, the home of Stan and Pattie Frost Jones, is a sustainable home designed to be self-contained, located 5 miles south of Marshall just off the French Broad River. Used automobile tires filled with rammed earth are stacked like bricks to form the foundation and load-bearing walls of the Earthship. The front of the house is sloped, featuring insulated glass panels, and the north side is earth-bermed. A greenhouse with a variety of plants lines the front interior. Natural daylight ensures that the spaces are lit well. Several nonload-bearing walls are constructed of mortar and aluminum cans.
The site selection has several advantages. The site has full solar exposure all day, and no ridges or woods shade the front of the house. In addition, the land is a meadow, so no sizable trees were removed. The house is situated to create drainage away from the structure.
Besides the site, the systems in the house contribute to its energy efficiency.
Heating and cooling system
The design of the Earthship is key to heating and cooling the house. A wall of glass on the south side of the house is sloped to optimally capture the winter sun. Heat from the sun’s rays heats the space. The mass of rammed-earth tires and concrete stores the heat. When the temperature inside the space drops below the temperature of the mass, the mass begins to release heat into the living space. Sloped glass also helps the Earthship interior remain relatively cool. The summer sun is high in the southern sky, which means the sun’s rays only reach the front of the house that time of year. Additional shading is needed in the summer months. An important component of Earthship design is the cross- ventilation from southern windows and skylights in each room. Air passing through the southern windows picks up heat and remove it through open skylights.
Electricity is provided by a photovoltaic array of eight 150-watt panels. Batteries inside the house store enough power to make it through cloudy days. An inverter converts DC power to AC power to make electricity to run household appliances. Lighting for the house is both DC and AC. Compact fluorescent bulbs are used throughout.
The roof of the Earthship is designed to catch rainwater. The slightly sloped roof drains rainwater into cisterns located on both ends of the house. From the cisterns, the water is pumped (using a DC pump) into a pressure tank. This is the water supply for washing clothes and dishes, showers, watering plants and other needs. A solar water heater is planned. Now, hot water is furnished by a tankless, on-demand propane gas water heater. The water heater will be a backup during consecutive cloudy days.
The house has other energy-efficient features.
The entire length of the Earthship is a planter bed. A variety of plants can be grown for food, beauty and shade.
Wood trim around windows and doors was made mostly from salvaged redwood. Earthship doors were hand built using reclaimed wood from pallets. More than 1,200 SUV tires were saved from the landfill to construct the load-bearing and thermal mass walls. Bottles and cans were used in the construction of the nonload-bearing walls. Plumbing fixtures were purchased at the Habitat for Humanity store.
The main finish material inside the Earthship is adobe plaster made on site with earth from the excavation. This and the stone surfaces are sealed with nontoxic sealers. Concrete countertops and slabs are finished with nontoxic concrete stains. All interior wood doors, ceilings, trim and cabinets are finished with tung oil.
[Stan Jones has worked in construction as a designer and construction administrator for 25 years. During this time he has received training in solar greenhouse design and construction. He has just started a design/build business and also works as a general contractor.]
[Pattie works toward the protection of the natural environment. She has a Bachelor of Science (Ecology and Field Biology) and a Master of Public Administration (Focus on Natural Resource Policy). While living in the Pacific Northwest United States, she worked as a field organizer and public outreach coordinator for several environmental organizations.]