Straw is a wonderful building material, it is widely available, sustainable, cheap and a marvellous insulator. Straw has been used in constructionl through the millennia, usually mixed with earth in various proportions where it acts as reinforcement and insulation. Three of the ways that straw can be employed are described below.
The most common type of earth and straw buildings in the UK are cob buildings mainly found in Devon, many of which are hundreds of years old. Cob buildings have weight bearing walls containing a high proportion of clay to a relatively small amount of straw.
In the early 1900's the invention of the mechanical baler in the USA gave rise to the first straw bale buildings, many of the originals still survive and are in use to this day. Much has been written about this technique with many beautifully illustrated books available. There is an increasing number of examples in the UK.
In continental Europe a slightly different technique evolved that employed a timber frame to support the weight of the roof. Straw mixed with liquid clay was then used as a bulk infill material. There are countless examples of these buildings across northern and central Europe, the majority of which are many centuries old. This technique goes under a variety of names - "Method Hirondelle" in France, "Leich Lehm Bau" in Germany - and translates into English as "Light Earth" or simply "Straw Clay".
These three techniques are examined in more detail in the following pages.