Our office was involved in this project for the preparation of the required study of structural assessment and retrofitting of the existing five-storey building, with two basements, made of reinforced concrete, in the framework of the project “Change of external facades and internal layouts, remodeling of the surrounding area, drilling holes and structural reinforcements in an existing office building with basements”. The building had a provision for remodeling the entire building, which included adding exteriors, filling large holes in the building, drilling new holes, planting existing exteriors, adding an extensive pergola on the top floor, etc. The load-bearing structure of the existing structure consists of reinforced concrete beam-and-beam frames. A pushover was performed for the assessment check (ΚΑΝ.ΕΠΕ, § 5.7). The analysis and assessment check were performed with FespaR 22 v.8.3.0.16 software from LH Software, Steel Express and Beton Express from Runet for checking individual steel members, strength moments of concrete sections, strength moments of reinforced members, etc. Finally, excel sheets were also used as part of the CFRP beam and slab strengthening process.