[Ann Vole]

If properly constructed, the only problems I see with straw are the lack of consistency in insulation value and rather thick walls. Moisture really messes with the insulation value where both being too dry or too damp will lower the effectiveness.

The only other con is the lack of expertise, training, and standards in using this material and the resulting reluctance for building officials to approve building projects with straw.

Also note that there is a wide difference in effectiveness of different types of straw and hay for each type of construction and typical local weather for the building so a possible con is the lack of testing for the locally grown straw or hay you may choose to use.

Some pitfalls of improper construction can include: rodents or other pests nesting in the walls, air leaks or improper vapor barrier design causing moisture related problems like mildew and insects, wall integrity compromised due to settling of the foundation or improperly build window or door openings, stucco or wall cracking due to lack of tension in the binding materials, bad materials in the surface covering that fail to provide the tension element or otherwise fail, electrical fires due to not making electrical boxes air-tight or moisture tolerant, roof rain water getting in the walls, ice-jam problems if the roof is not made a "cold roof" in locations (with weather that includes heavy snow and multiple thawing events), lack of slope in the wide window ledges can cause many problems both inside and out