Investigation and conservation of artificial stone facades of the early XX century: A case study

The investigation and conservation of artificial stone facades, realized between the late XIX and the early XX century, have recently gained increasing attention, due to different reasons: on the one hand, the interest in documenting the architectural and technical characteristics of a relevant phase in the evolution of the building technology, whose historical and cultural values are commonly recognized; and, on the other hand, the need to deal thoroughly with the occurring alterations and pathologies. Particularly, the diagnostic process, although based on well established procedures and techniques for natural stone, should be carefully planned for artificial stone components, which show specific features, in terms of mixtures, installation and connection methods, interaction mechanisms with reinforcement and support materials. As a result, the definition of a correlated system of onsite tests and laboratory analyses is paramount, in order to come to a comprehensive qualification of materials, construction techniques and state of conservation, also by saving time and money. Specifically, the paper is going to describe a general investigation methodology for artificial stone facades, realized between the XIX and XX centuries, in terms of selection and correlation criteria of diagnostic techniques. The methodology has been applied to a case study, the social housing complex ‘‘Duca degli Abruzzi’’ in Bari, South Italy, that is particularly representative for construction history, extent and variety of ornamental elements, environmental factors and utilization conditions. The results from the characterization of mixtures, construction techniques and decay patterns have allowed the definition of compatible and suitable conservation measures.