Due to increasing environmental pollution and industrialization, old stone structures are now in jeopardy. A concern for the security of people and property was the first and foremost motivation for research into methods of examination upon which to base judgment of the state of a given structure with a view to the necessary intervention. The diagnostic studies of structures respectively under and above ground are fundamentally different. The final aim consists in determining the conditions of ulterior use of the structure. The study deals with underground stone structures. The system of control over above ground structures has already been published. From what was learned from examinations and the analysis of deteriorations, important points of view emerged which present a durable solution for the protection of new constructions.