The purpose of this paper is to explore the multiplicity and complexity of possible legal frameworks for building sites and the use of legal sources in the study of building sites in Rome and the Roman world, between the second century BC and the third century AD. The rst part presents the legal contracts, which could be used, and describes the organization of a building site under the locatio conductio, which is the best known and most attested type of contract. The primary sources used include the jurisprudential literature, authors such as Cato the Elder, Cicero, Vitruvius and Pliny the Elder as well as epigraphic sources. The second part of the article highlights the role of local residents on the one hand, and taxpayers subject to work obligations on the other hand, in certain public projects, and is based on the Table of Heraclea, the municipal laws of Hispania Baetica and the inscriptions of the "fullers' canal" in Syrian Antioch. The third part, based mainly on the jurisprudential literature, describes the appeals which could be lodged by individuals who were opposed to a building project, the consequences which these appeals could have on the project, and their contribution to our understanding of the relationship between public and private spheres.