Cast & Character: Building a Home With Cast Earth Construction

Building with Cast Earth

Harris Lowenhaupt, a Phoenix-based metallurgist looking for a way to make earth construction a competitive alternative to wood framing, invented cast earth in 1993. Because the tricks of the trade are closely guarded, the only way to build a cast earth house is through a licensed, certified professional (for more information, visit www.michaelfrerking.com). It’s made by combining dirt (with less than 20 percent clay content), calcined gypsum (a hardener and stabilizer), water, and a retarding agent that Lowenhaupt, who has applied for a process patent on the technology, considers a trade secret. Under normal circumstances, dirt and calcined gypsum harden almost immediately when mixed with water. Lowenhaupt’s proprietary retarding agent keeps the cast earth material in a liquid slurry state for anywhere from fifteen minutes to eight hours, enabling building contractors to pour it like concrete. The cast earth is poured into wall forms, which also contain electrical conduits, plumbing, block-outs for window and door openings, and insulation. After the mix has set, a reinforced concrete bond beam is usually poured in the top six inches of the wall, and after it has set the forms are stripped for reuse.

Michael Frerking, a cast earth affiliate in Prescott, suggests using the following criteria to decide whether a cast earth home is right for you. Your region should have at least 40 percent sunny days during winter; daily temperature swings should not vary between more than twenty and thirty degrees Fahrenheit; and annual rainfall should be thirty inches or less.