The article is devoted radionuclides (such as radon). This article discusses the causes of radionuclides and their main sources. It is known that the main sources of radionuclides are natural (70-80%), but without anthropogenic factors radionuclides would not be so dangerous, therefore we consider the reasons of increasing concentrations of radionuclides in the environment, ways of their penetration in buildings and structures, and identifying the most dangerous. Also examines the impact of construction materials on the concentration of radionuclides and selects the most harmless. Based on all of the above features protective measures to reduce the the concentration of radionuclides in the premises, and the various measures to be taken on construction stage and the operation phase.