EXPERIMENTAL EVALUATION OF PERFORMANCES OF DIFFERENT SOLUTIONS OF FINISHING FOR MASONRY BUILDINGS FOR DETERMINING DURABILITY

The components of the building envelopes have to provide performances of different types: it is supposed to resist to the weather agents, to have a good water vapor permeability in order to prevent some degradation phenomena, and to inhibit the capillary rising dampness. But it must also maintain all these features over the time, in other words it must have a high durability. The designers, when they have to choose finishing solutions, are put in front of very complex evaluations, with the aim of finding the most appropriate one, given the specific context stress factors. To provide a useful guide for those frequent situations, two Departments of University of Naples Federico II conducted combined tests in the laboratories and on the field, on four types of finishing solutions (plaster + painting) for tuff masonry, which is typical of Southern Italy. In the DICMAPI laboratory the specimens were subjected to tests of water absorption by capillarity, tests of water vapor permeability, tests of water absorption at a low pressure, and tests of accelerated aging in a QUV machine. The field assessments were carried out on 500 sampled buildings in the city of Naples, over 10 years of monitoring, showing the different behavior of the four types of selected specimens: for example, the characteristics of the finishing solutions of macroporous plaster + silicate paint and cement plaster + quartz paint have remained almost the same, without significant performance decay. The results could represent a good starting point for the creation of a useful handbook for designers of recovery interventions.