Methods and approaches to determining the residual resource of construction objects are considered, methods are analyzed to select the optimal one. To calculate the residual life of structures of the industrial workshop in the city of Saratov, a complex method was applied based on probabilistic methods (for structures whose strength characteristics were determined by non-destructive testing) and using graph theory (for other structures, the technical condition of which was established by external signs ) The established value of the residual resource (time before the onset of an inoperative state) before the reconstruction was 3.8 years, taking into account the operation of structures in the industrial enterprise mode. The residual resource of the building in the mode of the shopping center was 18.1 years, taking into account the reduction in operational loads (there are no crane loads, the roof structure was changed), this resource is insufficient for the object put into operation. In the process of reconstruction, communications, external and internal decoration, improvement of the adjacent territory were restored, truss structures were strengthened, the structures of the coating and external walls were partially replaced. The technical condition of the building was improved, which is reflected in the residual life - 64.7 years, which is more than the design life for buildings of this type. Therefore, a comprehensive calculation of the residual resource is an effective method for determining the scope and types of work on reconstruction and restoration of buildings.