One of the most frequent defect in building is appearance of moisture. Due to the growing social awareness and environmental policy, it becomes necessary to evaluate the behaviour of a new construction materials regarding this kind of defects. This paper studies the behaviour of masonry mortars incorporating three types of recycled aggregates: concrete, ceramic and mixed, with dosages 1:3 and 1:4 to be compared to the behaviour of traditional mortars in terms of absorption by capillarity, rainwater penetration and water vapour permeability. The results show that under condition of water absorption by capillarity or heavy rains, ceramic recycled aggregate has the poorest behaviour due to its high mix water absorption. Moreover, water vapour permeability is higher in mortars performed with recycled aggregates, minimizing in this way the condensation that can be produced in interior spaces. Key words: masonry mortar, recycled aggregate, moisture, defect.