Larry Strain authored the guideline environmental building specifications (formerly published as ReSourceful Specifications) included in the The Specifications provide selection criteria and performance standards needed to specify materials and methods of construction that are more environmentally responsible. It supplements the existing criteria, definitions and standards contained in a set of standard building specifications, with additional environmental requirements such as resource and energy efficiency, use of less toxic building materials and waste reduction.

GreenSpec covers innovative materials such as straw bale and stabilized earth, as well as how to use more common building materials and practices such as wood and concrete in a more environmentally responsible way. The current edition contains 33 specification sections in divisions 1 through 16.

Buildings consume 40 percent of the world’s resources. Furthermore, 50 percent of the energy in this country goes directly or indirectly into buildings. Their impacts on the ecological systems that support life – from the ozone layer to global warming to the world’s forests – are staggering. The construction of a typical home in this country consumes about an acre of clear cut forest and generates roughly four pounds of waste per square foot. Changing the way we build has become a priority.