At the Sage Mountain Center, timber frames the main building, whose north and west walls are straw-bale infill with an insulation value of about R-40. R-value is a material's measure of resistance, per inch, to heat flow. At its best, straw bales measure about R-2 per inch when a bale is placed on its side in the wall, averaging about 20 inches in width. The south and east walls are cordwood, at R-25, with an interior eight-inch bed of sawdust. Positioning cordwood in the south wall-along with the thick layer of insulation-creates a high thermal mass that stores energy "like a battery" throughout the 24-hour cycle of large fluctuations in temperature, says Welsh.
Sage Mountain's energy feeds from a combination of solar and wind power, which, along with wood-burning stoves in the winter, heats the center's air and water and powers the electrical appliances. The structures consist of the main building, where they conduct classes, a one-and-a-half story guest cottage, and a one-room cottage, named Tilting Tree Cottage due to the angle of a large nearby tree.
The current economic meltdown, and specifically the housing-market crash that is casting thousands of homeowners out of their homes, gives owner-builders an additional, acute reason-on top of climate meltdown-to consider building sustainably. Much like the illusion of security that became endemic throughout the home-financing world during the first decade of the 21st century, the buildings in which we typically spend vast amounts of time do not meet the basic needs of the surrounding ecosystem. And such a statement in itself leads to the question what does sustainable mean?
Thanks to Simmons Buntin