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The Walls of Gubbio exhibit several issues related to the materials degradation (limestone, travertine, sandstone-serena stone, plasters, binders) used for building and restoration. These materials suffer of increased deterioration due to climate change effects coupled with pollution. The degradation effects of the outer surface are:
- loss of material (formation of hollows, differential degradation, erosion, gap, lacking, pitting)
- decay of the m...
Similarly to the case of the Town Walls, the degradation of materials is strictly related to the Climate Change effects combined with the pollution. The stone erosion by dissolution of carbonates and/or the stone blackening, especially affecting limestone are observed as an immediate consequence of these effects.
Blackening on one of the columns inside the palace (left). Damages due to freeze-thaw causing loss of material (right).
The Problems evidenced in Knossos:
- the degradation of selenite (mineral gypsum). This material is particularly sensitive to a number of factors, relative humidty being the most important
- salt accumulation and efflorescence in sheltered areas due to incompatibility of adjacent materials (i.e. selenite/cement interface,) applied in different periods and conditions and/or to the presence of humidity c.
- dark encrustations and other external accumulations A number of encrustations of different colour, texture and origin can be found on the surface of the Kn...
Extreme climate events, most in terms of heavy rain and its local effects, are causing structural instabilities for the overall historical area, as testified by the existing and progressive slow deformations and crack patterns affecting the ancient structures (see pictures with examples below).
