This project was about the investigation and geometrical documentation of the structural system of an existing two-storey building. Furthermore, the assessment of the physical and mechanical properties of its construction materials was also implemented. The aforementioned tasks were carried out in the framework of the following possible modifications: construction of an extra floor and adding of both a new interconnecting staircase and lift-core. The building is made of reinforced concrete and it is located in the intersection of Meteoron and Amitoros streets, in Pagkrati, Athens. Moreover, it was constructed in 1954. The implementation of all the required tests of the load-bearing elements of the building which are described in the Intervention Regulation were also included in our services, such as radar scanning of reinforced concrete elements for the detection of steel rebars, exposure of steel rebars, carbonation test (use of phenolphthalein solution) and rebound hummer test.