In the west, the Uniform Building Code, or UBC, is the predominant model. Thus, a typical bale consists of a series of 4-inch (102 mm) flakes compressed along the long axis. In 1997, Pima County, AZ, adopted the first prescriptive code for load bearing straw bale structures. This practice in not advised when obtaining insurance. The different types of grain straw have varying chemical compositions and inherent strengths, rice straw being perhaps the toughest due to an unusually high silica content. Any plaster is far stiffer than the straw, and will therefore “attract” any subsequent loading, much as a sharp stone in the sand will “attract” the weight on your foot. Our experience in working with Terry Phelan was exceptional! In a more elaborate system developed in Canada, stucco mesh sheets on both faces of the bale wall are grabbed from the top with oak bars, tightened upward with car jacks or inflatable bags (which push down on the top plate, compressing the straw) and secured in a taut condition. The structural model is complex: Rigid inside and outside skins are attached to the comparatively soft straw-bale “masonry” assembly. She has a team that truly listens to your goals, and makes them happen! Even for a post-and-beam structure, this can be a problem, as degradation of the straw leaves the plaster unsupported and can release mold spores into the air that may be hazardous to health. All these systems show more promise than the all-thread systems because the tighter spacing allows for some leveling of the wall top by adjusting relative tensions, and because their elasticity (springlike behavior) permits them to maintain some compression on the wall even if it settles. House building becomes a community effort, with the volunteers learning a new skill and the homeowner receiving valuable assistance at little or no cost. Water penetration, as with any other type of construction, is a potential problem. Builders report that plastering is made more difficult because the straw is presented across the face of the exposed wall, as opposed to the end grain exposed in a flat-stacked wall. Internal pinning of the walls (with rebar dowels) has been prescribed in straw-bale codes to date, but is an area of some controversy, for it is not known how much contribution internal pins make to the strength of the finished wall assembly. What are the best resources to learn more? We can't recommend Living Shelter highly enough. Never tuck the bottom edge beneath the bale; it creates a “bathtub”. Tests have shown that bales on the side have a little load-bearing capacity but have a higher R-value per inch, so the net thermal insulation of an edge-stacked wall is about the same as a flat-stacked wall. The straw tubes are springy and high in tensile strength. Laboratory fire tests conducted at the Richmond Field Station in 1997 by students at UC Berkeley rated a straw bale wall at 2 hours burn time. Moisture content will depend on the circumstances at the time of baling and during subsequent storage and transport; quality control and inspection of a straw-bale job requires the use of a bale moisture meter, available from farm supply houses. As long as the bales are kept dry, you should not have any problems with rot or fungi. As in conventional construction, exhaust moist air from kitchens and bathrooms to prevent excessive interior moisture, and many suggest using a low permeability latex paint on interior straw walls to inhibit moisture migration in these areas.