This article is about the conservation and restoration of Brazilian patrimonial fortifications and it is approached since a theoretical and methodological use of lime. It is based on the current tendency for a sustainable conservation of the cultural goods by means of using the same materials originally found in them; it discusses the relevance and the cultural - historical scope of the Brazilian patrimonial fortress; it describes, using examples, the characteristics of the construction of the parameters, the mortars and the problems commonly found in the conservation of the buildings. Finally, the article proposes some practical orientations for the use of the lime in conservation projects and general directives for projects and programs of technical collaboration.