Loam plasters consist mainly of sand and silt with only as much clay as is necessary (usually between 5% and 12%) for developing their adhesive and binding forces. It is difficult to determine the proportions of an ideal loam plaster, because not only the proportions of clay, silk and sand influence a mixture’s properties. Other factors affecting the composition are the grain size distribution of the sand fraction itself, the water content, the type of clay, the method of preparation and the additives. In order to test the appropriateness of loam plasters, samples with varied compositions should be tested. If the surface is rough enough, then loam plasters stick well not only to loam surfaces, but also to those made of brick, concrete and stone. For the ability of loam plasters to balance indoor air humidity see chapter 1.