The protection against water penetration results from the water permeability of the respective product, which is classified for façade paints in DIN EN 1062-3. The water permeability rates (W-values) of façade paints are divided into four classes W0 – W3. The lower the W-value, the lower the water absorption and water permeability, and thus the higher the protection of the substrate:
Source: bauwion
