Melissa Hofmann, Gettysburg Times via AP Lee and Cheryl Sornson's new house is being constructed with walls of straw and clay. Click photo for larger image.

FAIRFIELD, Adams County -- Like any number of other people, Lee and Cheryl Sornson are in the process of building a new house. Unlike most, however, they are currently spending their days stacking hay bales and spreading clay.

For the Sornsons, it's only natural. The couple is trying their hand at "natural building," a trend that is gaining popularity across the country as evironmental concerns are becoming a major issue. This type of construction is non-toxic, sustainable and evironmentally friendly -- "green," as Cheryl says.

Located just off Orchard Road in Liberty Township, Adams County, the Sornsons' new home consists of a timber frame with walls made of a combination of straw and clay, which the couple says is one of the most efficient types of insulation available.

"It's (comparable to) an R-40 or R-50 (heat resistance value)," said Lee.

This type of construction is also the most durable and long-lasting, says Lee. "There are buildings like this in Europe that are 800 years old," he said. "The oldest buildings in the world were made like this, with straw and clay."

The Sornsons, who own and operate Piney Ridge Timber Frames, have been interested in this type of project for years; however, this is their first foray into natural building.

"Our old home was timber frame and logs," said Cheryl, "but when we acquired this property we wanted to build this type of house." The couple is working on the home with help from Ohio-based Fox Natural Building. The company has worked on three such homes this summer alone, including the Sornson home, said owner Chris Fox.

Construction on the home began this spring, and the frame itself was raised on June 5, said Cheryl. The straw was put in the walls last week, and this week the crew began plastering the indoor and outdoor walls. The home is expected to be finished by December 1.

When completed, the 2,900-square-foot, two-story home will contain three bedrooms, three full baths, a great room, kitchen and a loft area.

The home's interior walls will be done in a number of clay finishes, some smooth and some allowing the straw to show through. This, along with the timber framing and exposed beams, give the home an artistic feel, said Cheryl. Siding will be put on the south side of the house to protect it from exposure, she said, but the rest of the home's exterior will feature only the clay plaster finish.

The home's framing and walls are not the only environmentally friendly aspects the Sornsons have planned. The hot water for the home will come from solar power, made possible by the home's hilltop location.

"We're still working on the heat (source for the home)," said Lee, noting that it would also be "something green.'"

The house also takes safety into consideration. The home's walls, though made of straw, are fire-retardant. Should a fire occur, "it would be like trying to burn a phone book because it's so packed together," said Anna Wolfson, a plaster specialist with Fox Natural Builders.

"You can't burn the clay either. It's like ceramics," she said. Wolfson also said it's important to make sure that the walls are packed tightly to resist air and moisture or the straw will begin to rot.

Overall, a home like the Sornsons' costs more than an average home, mostly due to the timber framing, they said. "The frame will cost about 10-15 percent more," but "the cost is comparable to any other custom home," they said.

As for other such homes nearby, Lee noted that there were a few in the Hanover area and a few near Frederick, Maryland. The Sornsons' natural-built home does not require any special permits or other licenses, he said.

The couple, formerly of Biglerville, along with their 5- year-old son, Levi, are temporarily living near the site in a trailer as they work on their home.