Sustainability
Although cordwood homes have been tested in -40F locations like Alberta, their thermal efficiency in any climate is below that of a purely cob house of comparable dimensions. In frigid areas it is appropriate to either build a thicker 24-36 inch wall, or two separate super insulated walls. In predominantly wet areas, the outside walls can be plastered, smothering the cordwood ends from air and moisture, but this hides cordwood's attractive log ends and the logs will rot. The quantity of labor relative to gaining a specific R value for cordwood is higher when compared to straw bale and stick frame construction. Funds saved in construction may need to be allocated for heating costs or longterm exterior maintenance. An organic, mortar-like cob creates less of an environmental impact because of the use of readily available mud and straw, whereas toxins emitted during the production of Portland cement are very harmful, albeit less tangible in the final product. Like many alternative building styles, the sustainability of cordwood construction is dependent upon materials and construction variables.
Following the Cordwood Conference in 2005 at Merrill, Wisconsin, a document was published to address best practices in cordwood construction and building code compliance.The document entitled Cordwood and the Code: A Building Permit Guide assists cordwood builders get the necessary code permits.
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