The effect of metakaolin and hydrophobic agent admixture on properties of newly designed lime plasters is analysed in the paper. The overall majority of physical - chemical building deterioration is related to the penetration of moisture and soluble salts into the building structure. For that reason, the modified lime plasters were in the wide range of various properties tested. Comparative measurement declared the usage of metakaolin and zinc stearate does not significantly influenced basic physical parameters and water vapour transport, but reduced the liquid water transport which is very positive finding.