Building an Earth Bag Home Building an Earth Bag Home
As consumers, and especially as Americans, we are brought up to believe that "bigger is better." Now, with all the news about global warming and air pollution, it is time to redo our thinking. I find it hard to believe that a couple needs a 3 to 4,000 square foot home to live in. It is impractical, uses a great deal of energy, and uses resources above and beyond what our needs really are. There is a movement today to move back more closely to the earth, and to use renewable resources and resources readily available for building homes. Recent studies and experiments have proven that an earthbag home is environmentally friendly, energy efficient, and is built from local - and readily available - resources. This article will discuss earthbag homes, how they are built, and their advantages and disadvantages.
What Is An Earthbag Home
An earthbag home is nothing more than a home built out of bags of earth, stacked in certain patterns and on a solid foundation. They utilize local resources - the ground you stand on - for building material. Anything works - sand, gravel, scoria, which is volcanic rock, rice hulls - you name it and it probably can be used. Builders of earthbag homes try not to use wood as much as possible in building their homes, because so many forests have been depleted in the logging industry. Instead, they opt to build their earthbag homes with domes, which require no wood to finish. Where wood must be used, they use wood for such things as balustrades, stairs and railings. The wood is used in its natural shape, instead of being sawn into boards.
How Are They Built?
Simply put, traditional burlap bags or polypropylene bags (stronger and don't rot) are filled with earth. The combinations and textures matter little, as long as you understand that certain materials retain moisture, such as clay. Best mixed with a percentage of sand, the bags arte filled, stapled tightly shut, and stacked to build the outside walls of the home. Because many earthbag builders don't wish to use wood in their homes, a dome is often incorporated into the design so that rafters do not need to be put in place.
Doors and windows are incorporated into the design in several ways. Sometimes, a door is framed in using lumber, but typically the builder uses arched doors and round windows, thus eliminating the need for lumber in the build out. A lot of builders use metal farm machine wheels and culvert couplings for window openings. The options are endless. Nearly every earthbag home I have seen has had round windows. The outside is usually covered with stucco, papercrete, or stabilized earthen plaster. Many times an airlock is incorporated into the design to be more energy efficient. This serves dual purpose - the main door opens onto a room that can be used to store coats and boots, and then egress is made into the interior.
How Energy Efficient Are Earth Bag Homes?
Because of the design, giving thick walls and the insulating qualities of earth, these homes are designed to make good use of passive solar heat, facing south or east, depending on location. They homes are also designed so that sunlight during the day is absorbed by the interior walls, keeping the room warm after the sun goes down. Often, the only source of energy used is either fireplaces or small propane or electric heaters in individual bedrooms. An important step here is to insure that exterior walls are properly finished so that the daily heat from the sun does not leak back out in the evening.
Are There Disadvantages?
Much thought needs to be put into the final design. Material used to fill the earth bags needs to be stable and not contain moisture. Builders will put a small mixture of Portland cement into the bags for increased stability, depending on the composition of the filler.
Some people find the design of an earthbag home to be "heavy" and have the feeling of living in a cave. The earthbag home also requires a great deal of plaster in construction to insure water integrity.
Earthbag homes are a way for people looking for an alternative to the traditional stick built home. They are earth friendly, and use materials that are readily available. If you consider building one, be sure to check local codes and work closely with local building officials. The results are very pleasing, energy efficient and is kind to the earth.