What is Rammed-Earth Construction?

An ancient building technique revisited.
September/October 1999
http://www.motherearthliving.com/Green-Homes/The-Dirt-on-Rammed-Earth-Construction.aspx
A natural arbor and ­generous overhangs, above, ­protect rammed-earth walls in high rainfall areas.


Photo by Robert Reck

Earth-Construction History

Two of many ancient earth-building techniques—which include wattle-and-daub and adobe—-are rammed earth and pisé de terre, prehistoric construction methods that predate the development of the opposable thumb. In fact, 130,000 years after the appearance of the first homo sapiens, most of the ­planet’s species and 50 percent of its humans still live in shelters made of earth.

But today’s earth shelters are a far cry from those of our prehistoric ancestors; they can be as refined as a Mies van der Rohe, as polished as an I. M. Pei. There is archeological evidence nearly 10,000 years old of entire cities built of raw earth: Jericho, history’s earliest city; Catal Huyuk in Turkey; Harappa and Johenjo-Daro in Pakistan; Akhlet-Aton in Egypt; Chan-Chan in Peru; Babylon in Iraq; Duheros near Cordoba in Spain; and Khirokitia in Cyprus. All the great civilizations of the ancient Middle East—Assyrian, Babylonian, Persian, and Sumerian—built structures with mud brick and rammed earth. But their buildings were not primitive. They included monuments, temples, ­ziggurats, churches, and mosques.

The Tower of Babel, seven stories tall, was built of sun-dried mud bricks in the seventh century b.c. Excavations in China have uncovered rammed-earth construction also dating from the seventh century b.c. The Great Wall of China, built over 5,000 years ago of stone and rammed earth, remains one of the largest construction projects ever undertaken.

This unbroken tradition of earthbuilding survives elsewhere than in the Far East, where over 6,000 years of construction can be traced archeologically. It is ­particularly popular in Africa, the Middle East, and Australia where the scarcity of trees, low annual ­rainfall, and abundance of labor make earth the only logical building material.

From the time of the pharaohs, desert peoples have constructed villages of adobe and rammed earth. In Morocco, Berber tribesman continue to build rammed-earth structures to protect inhabitants from heat. Cities enclosed with rammed-earth walls created shade and protection from desert winds.

Rammed earth was brought to the more temperate regions of Europe by the Romans and Phoenicians. Pisé de terre became the dominant building method in the Rhone River Valley for 2,000 years because the soil that washed down from the Alps was ideal for rammed-earth construction. Even today, fifteen percent of the area’s rural builders continue to use pisé de terre.

In North America Jesuit priests introduced Christianity to California natives while teaching them how to make adobe, and Spaniards constructed the first permanent structures in St. Augustine, Florida using a mix of soil and shells rammed into heavy wooden framework. The result was pisé de terre, a construction method enjoying a brilliant renaissance in today’s architecture.

True Grit

  • Most builders outside Northern California and the Southwest have little experience with rammed-earth construction. However, contractors and builder-owners willing to learn the technologies can take workshops ­sponsored by Rammed Earth Works in Napa, California or the Southwest Solar Adobe School near Albuquerque, New Mexico. Or you can learn rammed earth yourself; start with a backyard bench, move on to a garden wall, then try a tool shed.
  • Rammed-earth structures can be built in any climate or locale if the design is appropriate. High rainfall areas demand concrete footings and generous roof overhangs. Hot climates require ample shading. Humid climates need good ventilation. Cold climates should have secondary wall insulation.
  • Wiring is identical to other masonry wall systems; it runs through conduits installed in walls and is accessible at all plug, switch, and junction boxes.
  • Plumbing is installed through floors and interior frame walls wherever possible. Repairs, when necessary, resemble those made to conventional wall systems.
  • Electronic reception for TV, radio, and cell phones is enhanced with an antenna, a satellite dish, or a cable hookup. Walls do inhibit the use of ­cellular phones, however.
  • All walls are load bearing.
  • Although many states do not yet have building codes for PISE construction, our work in high seismic-risk zones should make the permit process easy.
  • It may be possible to use the soil in your own backyard for PISE construction. However, it needs to be of the right materials and consistency for your geographic and lifestyle needs. (For information on soil testing, refer to the Appendix in The Rammed Earth House.) To find a testing laboratory near you, see the Geologist/ Testing Laboratories section in your local Yellow Pages. 

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