In this diplomic work, traditional roofs built tens or hundreds of years ago in the city of Zagreb were observed, as well as today's modern procedures for the restoration of such roofs with the aim of maximizing the use of the roof and the use of the space below it, with maximum preservation of the traditionality of all elements of the roof and roof structure. The types of roof structures and their characteristics were observed, and consequently the types of damage that occur due to adverse external influences on the wooden elements of roof structures or the passage of time. As the main core of this paper, the technologies of renovation and strengthening of such roofs are theoretically observed, with the definition of the purpose and method of implementing some specific method of strengthening the roof structure, after which four objects were observed on whose roofs reinforcement interventions were carried out or they will be according to the existing project in order to gain an insight into the real usability of the theoretically researched methods in practice. At the end of this work, a list of all strengthening methods known in this work is provided, classified according to the location or type of damage, and as an example, with the aim of guiding designers when defining work on strengthening roof structures, an example of a cost sheet is given for all, in this work, listed strengthening works.