Shelter in the Rammed Earth

Beat high building costs with rammed earth, the "dirt-cheap" alternative.


| January/February 1983



rammed earth - the Ruhtenberg rammed earth home

The Ruhtenberg rammed earth home.


Photo by Lyd Foote

Of the three types of soil-home construction commonly used today (adobe, pressed block, and rammed earth), I prefer the rammed (or tamped) earth method. I suppose the reason for this is that after five years of living in a home built that way, I'm 100% pleased with my sand-and-clay castle.

Rammed earth structures are generally made from soil that's dug up from the building site, shoveled into frames, and packed down to make walls. They can be built in half the time it'd take to construct an adobe house of similar size and are (I think) more attractive. In addition, they're dry, durable, economical, soundproof, and unaffected by fire and rot ... and because of the heat-harboring potential of their massive walls (usually more than a foot thick), tamped houses lend themselves well to solar applications. (In fact, they're naturally warm in winter and cool in summer.)

Backwards in Time

One of the earliest records of rammed earth construction can be found in the writings of the Roman historian Pliny, who described the turf towers built by Hannibal that stood for 250 years. The Romans, it's said, introduced this form of soil molding to France, where it's referred to as pisé de terre and is still widely used.

In the United States, the construction method reached the height of popularity in the 1940's when conventional building materials were being allocated to the war effort. But as soon as the struggle was over and the economy had recovered, making the more conventional materials once again plentiful and affordable, folks pretty much forgot about pisé.

Chinks in the Wall

Of course, new home builders didn't stop making rammed houses out of sheer fickleness. In truth, these dirt diggings do have some drawbacks, not the least of which is that — even though they don't take as much time to construct as can adobe structures — they do require a lot of hours and a good bit of hard physical labor to build (especially if most of the work is done by hand). For example, in one day you can expect to finish about 70 square feet of wall ... which many would-be earth rammers have decided isn't a heck of a lot of progress to show for the backbreaking effort expended.

The procedure goes something like this: First, you have to prepare the proper soil mixture (about 70% sand to 30% clay by volume. Then, if you like, add enough cement to equal 6% of the total). Next, you'll need to mix just the right amount of water to hold it together so it'll harden properly. And once you've laid down a concrete foundation and made, bought, or rented the cumbersome wooden — or metal — forms that the dirt's to be tamped into, you have to find some way to bully the sand/clay mixture into the molds.





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