Concrete is a fundamental material of modern construction due to its reliability, the ability to harden in air and under water, the ability to build structures of any shape and sizes. In particular, it is used in the construction of advanced structures and their parts: nuclear power plants, large hydraulic struc-tures, bridges, massive foundations of multi-storey buildings, etc. This paper is devoted to relevant objective in the field of construction of buildings and structures with a high level of responsibility, the study of thermal crack resistance of massive concrete structures, taking into account the temperature effects during the building period. The calculations are given of the thermal crack resistance of the foundation plate of the reactor department of Leningrad NPP-2 under continuous concreting with one block at full height. It is highlighted that the use of the simplest calculation model, which does not con-sider fluctuations in air temperature during the building period, leads to a significant error of the sur-face insulation thickness that is optimal from the point of view of providing the thermal crack re-sistance of a massive concrete structure.