Going Green!

Outdoor Education built the county's first permitted straw bale building in 2003 using a local contractor and hosting volunteer workshops. The result serves as a model for San Mateo County for alternative building with sustainable materials, as well as an indoor classroom and teaching tool for students attending Outdoor Education.

Why do we use straw bales in construction? Straw is an agricultural waste product that is typically burned, creating air pollution and health risks for people and animals in the area. Fortunately, straw bales have incredible insulating properties, in fact, nearly twice that found in a typical house. The Outdoor Education straw bale classroom maintains inside temperatures of 60°F to 75°F when outside temperatures are between 29ºF and 85ºF.

The straw bale building retains heat because of its passive solar design. Correct site orientation, double-paned windows, and overhangs allow heat retention with little energy expenditure. The cement slab floor serves as the thermal mass that regulates the temperature and is stained in a dark color to help absorb heat.

The frame of the straw bale house is built with 80 percent recycled lumber. Diverting this lumber from the landfill is an example of a sustainable practice, as most construction waste is not reused. In fact, nearly one quarter of the waste in San Mateo County landfills is from construction projects.

The straw walls are covered with earth plaster on both the inside and outside. This plaster is made from natural materials – clay, straw, and sand. The roof is painted with a nontoxic milk-based paint.

The energy for the lighting in the straw bale classroom comes from solar panels on the roof. The solar panels also power our electric garden tools without creating pollution or increasing carbon dioxide in the atmosphere.

Community workshops that focused on the simple nature of the straw bale construction process were both instrumental in the building of the straw bale classroom and inspirational to workshop participants. Outdoor Education staff and community members of all ages were drawn together to learn alternative building techniques.