Water vapour transmission rate (WVTR) is defined as the amount of water vapour transmitted from one face of the sample to the other per unit time and unit area, under specific conditions. In these experiments, the WVTR was measured by a gravimetric method, according to ISO 2528 standard. The samples were sealed with paraffin wax on top of aluminium cups containing anhydrous CaCl2. The cups were exposed to conditioned atmosphere (23 °C and 50% RH) for 96 hours and weighed at regular time intervals. The mass uptake was used to calculate the WVTR. Five samples were tested for each coating type.