This week, I was the lucky recipient of a rammed-earth bench in my backyard.
You may recall, a few weeks back I posted pictures of our backyard beautification-in-progress project.
You may recall, a few weeks back I posted pictures of our backyard beautification-in-progress project.
Soon after, I got a text from two Arizona State University landscape architecture students. One of them, Perry, had been here to attend the Wendy Rule concert last winter, and friended me on Facebook afterwards. When she saw my backyard posts, she asked if she and her partner could use our yard to complete their senior landscape project, a rammed earth bench or wall.
Rammed earth walls are constructed by mixing soil, lime and a small amount of cement as a stabilizer, and ramming it into place between flat panels called formwork. Thousands of years ago, workers would ram the end of a wooden pole into the earth mixture to compress it. The girls used a tamper, about a foot square of metal attached to a pole. Hard work!
When the formwork was removed, we had a compressed earth wall.
Rammed earth walls are constructed by mixing soil, lime and a small amount of cement as a stabilizer, and ramming it into place between flat panels called formwork. Thousands of years ago, workers would ram the end of a wooden pole into the earth mixture to compress it. The girls used a tamper, about a foot square of metal attached to a pole. Hard work!
When the formwork was removed, we had a compressed earth wall.
The color of a rammed earth wall is determined by the earth and aggregate used.
The ramming process proceeds layer by layer, which produces interesting horizontal stratification to the wall. Sometimes the layers are subtle, such a the ones in our bench. Sometimes they can be purposely dramatic, by using varying soil and aggregates.
Special effects can be created by the addition of different colored material in some layers, and elements such as feature stones or objects, alcoves or relief moldings can be incorporated into the wall.
While we didn’t added colored materials or stones to the rammed earth base of our bench, the girls cemented on a beautiful Sedona-red flagstone top.
Rammed earth is very strong in compression and can be used for multi-story load bearing construction. Research in New Zealand indicates that monolithic earth walls perform better under earthquake conditions. Because there are no flammable components, it is also fire resistant. And because there is no cavity to harbor vermin and nothing in the material to attract or support them, resistance to vermin attack (including termites) is very high.
Because rammed earth is porous by nature, a water repellant coating is often applied after the structure has “cured” and dried for several days. The girls will be back to paint our bench with a water repellant next week.
Evidence of ancient use of rammed earth has been found in Neolithic archaeological sites in China dating back to 5000 BC. Parts of the Great Wall of China were constructed using rammed earth technique and are still standing more than 2,000 years later.
After the U.S. Department of Agriculture issued instructions for how to build a rammed earth home in 1926, they became popular with poor farmers during the Depression. The method faded away after World War II.
Rammed earth is very strong in compression and can be used for multi-story load bearing construction. Research in New Zealand indicates that monolithic earth walls perform better under earthquake conditions. Because there are no flammable components, it is also fire resistant. And because there is no cavity to harbor vermin and nothing in the material to attract or support them, resistance to vermin attack (including termites) is very high.
Because rammed earth is porous by nature, a water repellant coating is often applied after the structure has “cured” and dried for several days. The girls will be back to paint our bench with a water repellant next week.
Evidence of ancient use of rammed earth has been found in Neolithic archaeological sites in China dating back to 5000 BC. Parts of the Great Wall of China were constructed using rammed earth technique and are still standing more than 2,000 years later.
After the U.S. Department of Agriculture issued instructions for how to build a rammed earth home in 1926, they became popular with poor farmers during the Depression. The method faded away after World War II.
But the technique is coming back into more favor today, as builders look for more sustainable and environmentally friendly building techniques that will not contribute to deforestation and greenhouse emissions.
In my opinion, it is a stunning natural element that adds to the beauty of your home.
Thank you, Perry and Mariah, for adding a beautiful and earth-conscious element to our back yard. I hope you both receive an “A” on your final for this project!
In my opinion, it is a stunning natural element that adds to the beauty of your home.
Thank you, Perry and Mariah, for adding a beautiful and earth-conscious element to our back yard. I hope you both receive an “A” on your final for this project!
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