This research aims to highlight the problem of creating various models that reflect the life cycle of the “building-base” system, and link the reliability of this system with its technical condition. Based on the proposed model of the life cycle “reconstructed building-base”, it is possible to regulate the condition of the building towards its restoration, changing the category of technical condition to higher and obtain new, adequate to the current state, reliability indicators. During the operation of this model, it is possible to control the system management on the basis of the obtained quantitative values of reliability. The result of the reliability calculation is the determination of such a technical solution of strengthening the “building-base” system, which will provide a given level of reliability. The research provides an example of the calculation of an operable monumental building before and after its restoration.