Effect of coatings on moisture and salt transfer phenomena of plasters

For the protection of masonries against salt dampness various plasters and coatings are proposed. In many cases the application of inappropriate materials accelerates the degradation process. In this work the performance of different types of premixed plasters, suitable for confronting rising damp problems, along with different coatings (silane–siloxane coating and potassium silicate paint) were evaluated. For this purpose water vapour transmission rate experiments for uncoated and coated plaster were performed. Moreover, in order to investigate the durability to salt decay, an ageing test, through repeated cycles of capillary absorption of sodium sulphate solution, on brick–plaster-coating systems was carried out. The ageing test was monitored with the aid of infrared thermography. The results showed that the applied coatings seem not to influence moisture and salt transfer phenomena. Moreover, the plasters which presented the ability to transport the salt solution from the brick substrate, assuring the brick durability, are preferable in respect to salt transport blocking plasters.