My name is Harris Lowenhaupt. I started professional life as a chemist with an MBA, spent most of my life as a metallurgical engineer and manager, and evolved into a CEO. You can click to see my resume' and a bit of personal data, or not click. Your call.

Before that professional life, I grew up in an adobe house in El Paso, where a great number of houses, light commercial structures and government buildings were made of adobe in the years before World War II. Since El Paso, and New Mexico just to the North, are some of the oldest European settlements in the USA, there are still a large number of adobe structures there today. (El Paso is often referred to as, "The largest town in New Mexico".)

First as children, and later as adults, we came to appreciate the great quiet, subtle power and energy conservation of the massive walls which surrounded us, and were sad and nostalgic that the fine earth structures of the past four centuries were no longer being erected in any quantity. If you have visited the What is Cast Earth? link, you have already learned some of the history of the now temporary demise of earthbuilding, so I will not elaborate further.

Post WWII labor costs made building with earth too costly and it had always been a very hard manual labor effort. In the mid 20th century, I noticed the "stick and stucco (or brick)" houses that were tormenting the architectural mainstream. I asked my father why people weren't building real houses anymore. He explained the labor cost issue with our traditional adobe construction.

He also explained that, in response to an early idea of mine, that earth walls can't be simply poured like concrete -- the mud would take forever to dry inside the forms and it would crack as it dried.

Retarders: A New Generation, Previously Unknown to the Gypsum Industry

As a child, and throughout adulthood, I longed for a method by which earth walls could be built using machinery instead of the intensive hand labor required by adobe or rammed earth. Finally, in 1992, I hit on an idea that just might work. After a little laboratory testing, it appeared that a mixture of soil and a little calcined gypsum showed promise. Shortly, the following structure emerged:

This was one of three little walls built to prove that the mix design would not crack and shrink as it dried. The problem in the past with pouring earth walls as a water slurry had been that shrinkage cracking almost always defeated the attempt. Because the gypsum (1) adds strength, (2) prevents shrinkage of clays upon drying and (3) expands slightly when it sets, shrinkage cracking is not a problem in Cast Earth.

This was done in the early stages of development via a small, hand-loaded concrete mixer, when I had not learned to retard the set of the calcined gypsum binder, and working time was extremely limited. By the next year, I had a mix design that would stay "open" for 15 to 20 minutes, and worked up enough courage to pour a small prototype wall using machinery instead of hand labor. Here's the result:

When this Great Wall showed no signs of cracking, and as it developed an exciting, rich texture as some aggregate was exposed, I worked to develop a retarder cocktail which would really open up the mix design to make it handle much like concrete. Finally I arrived at a mix which would stay workable for over 2 hours! I thought this was astounding, and set about erecting a prototype building. (Today, using an even more intoxicating retarder cocktail, the mix will remain open for eight hours or more, and what seemed remarkable then is now forgotten.)

The problem of retardation for longer time periods (several hours) had not been addressed by gypsum users. Traditional uses of calcined gypsum did not require the longer working time needed to process large volumes of Cast Earth using conventional concrete equipment. If the previously known retarders are used in quantities sufficient to yield long term retardation, the strength of the product is seriously degraded by the retarder(s). This problem was finally whipped when I found some chemicals which allow long retardation without excessive strength loss. These compounds had not previously been known to be retarders.

Now it was time to mechanize the process on a prototype full scale building: This is the first commercial application of Cast Earth, as the building was a curing facility for concrete block to will keep the block from getting too hot during the curing process in the middle of the cool summers in Boulder City, NV.

At the completion of this little structure, a couple who were planning to build a large rammed earth house visited Boulder City, and decided to become the first owners of a Cast Earth house. The walls for their building were completed in two days in the summer of 1995. Several weeks would have been required to build the same walls with rammed earth or adobe.

For a short description of the Cast Earth Process, use the The Cast Earth Process Description link on the Home Page.

Multiple homes and ancillary structures have been built in Arizona, Colorado, Texas and California. Other areas are under active development. A considerable amount of new interest is opening.

New Cast Earth Licensees are requested to eMail their interest in becoming Cast Earth builders, along with some Company and personal history, to build@castearth.com.

Thank you for taking the time to follow the story of Cast Earth.

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