Rammed Earth Construction

Although it never gained a significant foothold in the U.S., rammed earth construction has been well known in Europe since the days of the Roman Empire.
September/October 1973
http://www.motherearthnews.com/green-homes/rammed-earth-construction-zmaz73sozraw.aspx
The Alhambra in Spain is one historic building made from rammed earth construction.


PHOTO: FOTOLIA/AURIS

Ever since our remote ancestors learned to make or enlarge shelters by digging into hillsides, men have known the advantages of earth-walled housing: warm in winter, cool in summer, fireproof, soundproof, dry, and immune to rot and insect damage ... not to mention inexpensive. In particular, soil pounded to a stonelike consistency has all those virtues and is also very durable: One Roman writer of the first century A.D. claimed that rammed earth watchtowers built by Hannibal were still in use 250 years later.

There's no way to check that last statement, of course, but historians do feel sure that rammed earth was used by those expert civil engineers, the ancient Romans ... who brought the technique to France and thence to Britain. (The method is still sometimes called by its French name, pisé de terre.)

Although rammed earth construction was well known in Europe, the early settlers of America didn't seem to use it very often. Timber, after all, was plentiful over most of the East. . . and since the pioneers of the treeless prairies thought of earth housing as a temporary expedient, they found sod perfectly adequate as a building material. In the Southwest, where soil structures were and are widespread, the usual choice was adobe (formed by molding and drying, not by compression).

Still, the method wasn't altogether lost, and interest in it flared briefly during the Depression when the cost of housing became a major concern. Several excellent studies—now out of print—were prepared at that time. A good example is Rammed Earth Walls for Farm Buildings, a report from the Agricultural Experiment Station of South Dakota State College on research carried out during the 30's. (John O. McMeekin, author of the article that follows, found that work invaluable when he built his own pise house over 25 years ago, and was kind enough to let us refer to his treasured and irreplaceable personal copy as we prepared this feature.)

After that flurry of interest, rammed earth construction dropped out of sight again in the building boom that followed World War II ... perhaps, as Mr. McMeekin wryly suggests, because nobody makes a buck on it. Certainly no contractor got fat on John's substantial home: It's his own work from foundation to wiring, cost him $6,000 and measured up to contemporary buildings that carried $15,000 price tags (just double those figures for equivalent prices in 1973 dollars). Ken Kern, author of The Owner-Built Home, mentions in his useful chapter on rammed earth that—at about the same time McMeekin was pounding away at his walls up in Pennsylvania—an Oklahoma professor of civil engineering put up a modest five-room dwelling, complete, at a total cost of just $887.50 ... so John's bargain was certainly no one-of-a-kind deal.

Nowadays, what with the renewed interest in non-destructive technology and the growing hunger for the satisfaction of producing one's own shelter, low-cost housing is back in the news ... and so is rammed earth, one method that's within most people's financial reach and practical ability.

Which is not to say that there's anything effortless about this way of building. On the contrary, rammed earth is—as the economists say—"labor-intensive" (one good reason why contractors don't attempt it). The making of a pisé wall involves a long process of setting forms, mixing soil and tamping it vigorously, layer by layer, until the pressure creates an artificial sandstone that rings like rock under your strokes.

Hard work, yes, but you can do it yourself ... and, since the only material needed for such construction is a soil with an acceptable sand/clay ratio, the makings of such walls are available to many of us free for the taking. No wonder the idea has never caught on with the commercial building industry!

(Ironically enough, a valuable government publication on the subject—the Department of Housing and Urban Development's Handbook for Building Homes of Earth— is intended mainly for self-help programs in underdeveloped countries and isn't distributed domestically because some of the practices it describes don't conform to American building codes. If your own homestead's self-help program includes a plan for earth housing, however, you can obtain a copy—ask for PB 179 327—from the U.S. Department of Commerce National Technical Information Service.)

Meanwhile, John McMeekin—an elder statesman of rammed earth building—still lives comfortably with his family behind his well-tamped walls, grinning at the weather and at all the people who thought he was insane when he launched his project a quarter-century ago. "This place will still be here a hundred years from now," says John.