In the process of implementing construction projects, an important factor is to prevent the occurrence of risks that negatively affect the timing of the erection of the object, the cost and quality of work. An important element in evaluating the duration of construction work is labor productivity. The purpose of the study is to identify and analyze the factors affecting labor productivity in the erection of brick walls of low-rise residential buildings, as well as the development of a probabilistic mathematical model for evaluating the reliability of a construction technological system based on the productiveness of brickwork. As part of the study, daily monitoring of the erection of brick walls was carried out. The monitoring was carried out at five construction sites for eight working weeks. In the course of the study, the cause-and-effect relationships of the formation of labor productivity of masons’ brigades with the organizational form of the “threesome” and “foursome” types were revealed. As result of the research, a probabilistic mathematical model for assessing the reliability of the erection of brick wall according to labor productivity parameters has been developed. The developed model allows us to assess its condition with respect to complete reliability, equal to one. The developed probabilistic model for evaluation of the reliability of the technological system for the erection of brick wall structures allows, taking into account local conditions, to predict the state of production to minimize the time of work with the effective use of material, technical and labor resources. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.