By Kim Glovas

PHILADELPHIA (CBS) – Saturday is the 5th Annual Green Fest at the Silver Lake Nature Center in Bristol, Bucks County. And the center is showing off the construction of a building that will be totally off the grid.

Volunteers have been building the zero-carbon footprint structure since August. It’s an earthship, which is built from tires, bottles and other castoffs, so materials are cheap. Tires are pounded full of dirt, and three walls of the structure are complete.

Lorraine Skala, education director of the project, says work is continuing.

“We’ll have a roof up before winter, we’ll be working on the interior over the winter and we hope to have it open to the public in the spring.”

Skala is hoping people at the Green Fest will take a short walk through the woods and check out the construction site. She says it’s a way of getting people to think outside of the box, and build with the earth in mind.

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