We optionally provide finely chopped straw. This comes from wheat cultivation. Wheat stalks dried in open fields are crushed and chopped to obtain a fibre for incorporation into the mix. The length of the fibre varies between one and ten millimetres. The role of the chopped straw can be to distribute the stresses in themixture during drying, to make the mixture lighter, and to give the plaster better resistance to mechanical stresses.