The thesis is about describing the characteristics of masonry buildings and the ways of renovating them. I focused on old masonry buildings of stone and brick and I described some of the most frequent causes of deterioration. The ways of renovation are mainly focused on constructional reinforcement due to its importance to provide old buildings enough seismic protection and, at the same time, to adjust them to the needs of modern life. The second part deals with analysis of renovation of St. Florian's church in Fojana. I described the initial state of the building before the renovation. I gave a detailed description of all works which were carried out in the process of renovation. Due to the fact that the renovation has been done on the basis of my previous experience I verified some parts of the construction with the static calculation.