Mud is one of the oldest building materials known to mankind. It was used to build homes more than 4,000 years ago.

Today, homes are made of wood and metal. However, a school in Nevada County is teaching people about new-age-mud-building techniques. It's called The Natural Living School. Teacher and consultant Pablo Loayoza started it shortly after the 2008 housing market crashed.

"Everything we use is within 50 miles," Loayza said. "That's the key. Eighty percent natural and local."

Using natural materials save homeowners on construction costs. On average, Loayza sees nearly 30 percent in savings.

“We try to use materials available on-site," Loayza said, noting she's done extensive research on California building codes. "The basics are clay, straw, and sand.”

He knows how to get a natural home permitted in California. A few modern additions like a concrete foundation and wood support structures make the home earthquake safe. Once the walls are covered in mud, Loayza says they are virtually fire proof and energy efficient.

“You can get a permit and build natural homes in downtown Sacramento and even in downtown San Francisco,” Loayza said.

There is very little machinery needed to mix the natural material. A lot of the work is done by walking on the mud, sand and straw mix with your feet. Ashley McDonell is taking the summer long natural living class and hopes to put her new skills to use in her community.

"I hope to build my own home and support my community," McDonell said. "I want to help women and children that don't have access to affordable housing."

Loayza teaches students how to build a house in exchange for their labor.

The sweat equity building model brings down the building costs even more. The Natural Living School is building Maggie Johnson an art studio on her five acre Nevada County property.

“I am going to be about $10,000 under budget," Johnson said.

Johnson is comparing that to an estimate with modern day building materials. Cost was only part of her decision to build with natural materials. She wanted to work in an environmentally friendly art studio.

“We live in a world with so many chemicals," Johnson said. "So much so that we don’t even notice it. I wanted walls that didn’t have an off gassing. Building with mud was a no brainer.”

Many of his students have gone on to get contractor’s licenses and create their own businesses. Loayza says he welcomes the competition.

“The school is not interested in keeping or retaining everyone that comes in," Loayza said. "I want them to go out into the community and share their knowledge. I tell my students we are changing the world one house at a time.”