The constructions often present cracks or fissures resulting from the occurrence of important movements, due to, for example, the differential laying of foundations, temperature variations, execution of underground works near existing constructions (construction of tunnels, galleries, basements, etc.).

Being those cracks or fissures manifestations of structural behavior, there is usually interest in following the variation of its opening over time (monitoring), in several points of its development. The fissurometer is a small instrument designed to measure, in an expeditious and economical way, the relative movements that occur in a point of a crack or crevice existing in a wall, floor or any other structural element of a construction.