Water absorption coefficient (w)

The water absorption capacity of substances is specified by the water absorption coefficient w. It is determined by the ratio of the water amount absorbed (weighing before-after) to the factor resulting from the area and the square root of time (formula: w = m / (A · √t), unit: w = kg/m² h0,5). The higher the w-value the higher the absorption capacity. In the field of construction this property is decisive e.g. for the selection of building materials, materials for paintings, coatings, repair measures, etc. Appropriate classification tables can be found in the relevant literature.