The article is devoted to the problems of spontaneous construction in comparing the public interest in ensuring the sustainability of civil turnover, the introduction of as much property as possible through the elimination of certain defective legal regimes, as well as private interests of landowners, developers and some other participants in civil turnover (customers, contractors, equity investors, etc.). The approach to defining the essence of unauthorized construction as a way to acquire ownership of certain real estate, which has certain defects in the identification process, as well as in terms of behavioral and object perception of this legal phenomenon is determined. It is established that in the legislation of the European Union there is a perception of the property law (Germany, Austria) and the binding legal law (France) model of the legal nature of spontaneous construction. Ukrainian legislation reproduces the features of both models within the Civil Code of Ukraine and special regulations. It is emphasized that the law-making legal fact for the recognition of the relevant real right to unauthorized construction is a court decision or a decision of an administrative body. At the same time, in order for the emergence of property rights, the case law does not in any way level the existence of the procedure for putting immovable property into civil circulation. The judicial practice and the development of the science of civil law are analyzed, on the basis of which it is concluded that the current approach, which differentiates construction activities, endowed with signs of unauthorized construction, where the determinants are the place of its holding, the volume and quality characteristics associated with the lawful or illegal use of land. Given the behavioral or objective perception of the legal nature of unauthorized construction, an analysis of the case law of courts of various instances, resulting in the own vision of resolving legal situations to regulate public relations for unauthorized construction depending on the legal status of entities claiming to legitimize it, or the legal regime of such property. According to the results of the study of the content of the draft Concept of renewal of the Civil Code of Ukraine, attention was drawn to the prospects for further improvements in the legal regulation of civil relations in relation to unauthorized construction.