YOU CAN BUILD WITH SOIL-CEMENT BLOCKS

Image Gallery Author's barn was built of soil-cement blocks using CINVA Ram. It has already withstood a rainy Pacific northwest winter.

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A few years ago—while reading Ken Kern's fine book, The Owner-Built Home, I came across something which brought me right up out of my chair: the CINVA Ram, a manually operated machine that makes ordinary earth into substantial 4 X 6 X 12-inch construction bricks.

Since I'm always on the lookout for inexpensive building supplies, I was (to say the least) intrigued by the idea of turning soil into concrete-like blocks. I confess I was skeptical, however, that plain old garden-variety dirt?for gosh sakes—could be used as a construction medium here in the cold, damp eastern edge of Washington State.

After reading more about compacted earth, however, I learned that its main limitation?vulnerability to attack by moisture?could be overcome through the addition of cement to the raw soil as a "stabilizing agent". Well, that was enough to convince me to give it a try . . . so I chipped in with some friends on a CINVA Ram and proceeded to build my barn, chickenhouse, and hearth entirely out of soil-cement blocks.

Now, two years later, I'm happy to report that the structures have all successfully weathered one reasonably severe winter and, in general, have lived up to my highest expectations. Soil-cement not only has excellent insulative qualities but is strong, durable, fireproof, easy to work with, and extremely low in cost. (My blocks set me back three cents each . . . and they wouldn't even have cost that much if I'd not been forced to buy clay and sand to add to our silty local soil!) In short, soil-cement is everything I think a building material should be.

THE CINVA RAM

In case you're wondering, CINVA is an acronym for the Inter-American Housing and Planning Center of Bogota, Colombia . . . while Ram is taken from the name of Paul Ramirez, the Chilean engineer who invented this brick making device in the mid-fifties.

The CINVA Ram consists of a box or mold which is filled with damp soil?cement, and a lever-actuated piston that compresses the earth-binder mix. Once the mold has been loaded with the proper amount of material, the machine's operator then forces its long handle down with a pressure of 70 to 100 pounds (exerting, in turn, 40,000 pounds of pressure on the soil that is being compressed). The brick formed by this procedure is then ejected, set in a cool place, and left to cure for up to three weeks.

Though not technically difficult, making construction blocks with a CINVA Ram is what is known as a "labor intensive" operation. Four adults?working in an organized assembly line with the aid of a mechanized cement mixer?can produce only about 50 of the 4 X 6 X 12-inch bricks an hour. (Since a couple thousand of the blocks are needed for even a small house, you can see why few people ever attempt this construction technique alone!)

To be fair, though, and give the other side of the story: CINVA Ram bricks may, be labor intensive to fabricate . . . but they're also strong, durable, fireproof, cost very few out-of-pocket dollars, and have good insulative qualities. In short, if you've got more time than money, you want to build with native materials, and you need a structure that will last . . . a soil-cement mixture formed into blocks with a CINVA Ram may be just the answer for you (as it has been for me).

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