No architectural material has been more widely used throughout history as straw. From African huts, to thatched roofs in Asia and Europe, to its use as insulation in Native American teepees, nearly every civilization has made use of this nearly unlimited, easily renewable, and entirely biodegradable building product.
The world produces over a billion tons of wheat, rice, oats, and rye each year resulting in nearly twice as much straw byproduct. Although it is occasionally used today in architectural applications, it seems to be an underutilized material considering the abundant supply, it’s considerable insulation value, it’s easy malleability, and the fact that it requires little or no industrial transformation.
Left: Stramit USA. Right: Agriboard Structural Insulted Panels
Left: Compressed Straw Board. Right: Kirei board made from reclaimed Sorghum Straw.
In addition to traditional applications such as thatched roofs and straw-bale walls, more contemporary products and applications are being developed which make straw a logical economical and ecological choice for contemporary architectural practice. For example, compressed straw bales allow for a regularization of the organic material into a form compatible with standard construction practices. Research has shown R-Values as high as R3 per inch, meaning that 4 inches of compressed straw would surpass the insulating value of one inch of aerogel, but at a fraction of the cost and with minimal additional energy required beyond the original photosynthesis and agricultural input. In fact, unlike the vast majority of architectural materials, straw actually has a carbon positive effect, returning more oxygen to the air through photosynthesis while retaining carbon in the form of the structural cellulose. The idea of using straw as an architectural material implies a way beyond the approach to sustainability that is driven by increasingly complex technological solutions, into a realm where buildings become a part of the closed loop ecological cycle. Furthermore, it implies the potential localization of the material economy which might allow for for an alignment of ecological and economic flows.
S-House in Böheimkirchen, Austria, insulated with straw bales.
Material Strategies 