You may recall, a few weeks back I posted pictures of our backyard beautification-in-progress project.
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 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.
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!