The over 40-years-old housing stock from the industrialized mass housing era is today functionally deficient and does not meet the current needs of residents. In particular, there are numerous architectural barriers, the systems are worn and obsolete, and the number of housing types is very limited. Examples of the modernization of multi-story residential buildings (the article presents those from Russia and Ukraine) confirm that this problem is universal, and a significant improvement of the building’s. utility value can be achieved through a relatively small modification of the building fabric: precast concrete structures of the buildings prove to be flexible enough to accommodate deep changes. The authors present a concept of modernization of a building erected in a “large block” system, typical for the Polish housing of the 1970s in many cities. The case study concerns a particular building located in Lublin in one of the large housing estates – the concept of its modernization is compatible with the local spatial development plan, the proposed solutions are architecturally coherent and technically feasible.