Within the research project NAKI DG16P02M055, an extensive experimental and theoretical research of the influence of grouting on the physical and mechanical properties of brick and stone masonry is carried out. The focus of the research is to verify, in particular, the strengthening effect of selected grouting mixtures based on hydraulic lime (nano-lime), resins and silicates. The influence of grouting on the change of porosity, pore distribution, absorptivity and strengthening effect of grouting of historical brick, marl, sandstone, trachyte, limestone and mixed masonry with lime binder using various types of grouting mixtures in comparison with ungrouted masonry is evaluated. Particular attention is paid to the masonry damaged by cracks and cavities.