Leichtlehm has been used from the 12th century in Europe. It translates as light loam or light clay straw.
Clay is mixed into a slurry with water and then combined with straw and compressed into a frame or mould. It can be used immediately upon being well mixed or allowed to age for several days in order to allow the straw to absorb the extra moisture and thus create a stickier, more durable and more easily tamped mixture. The ratio of clay to straw can be adapted to increase thermal mass or insulation properties. Wood chips can vary in size from sawdust to chips 5cm in diameter.
Leichtlehm can be stuffed loose between rafters as insulation, with the clay discouraging pests.
Materials and Methodologies