The cathedral of Jerez De La Frontera (Cádiz, Spain): Stone degradation and conservation

In this paper, the alteration of the stone of the cathedral of Jerez de la Frontera (Cádiz, Spain) has been studied. Firstly, an environmental study was performed. Secondly, a physical and chemical characterization of building materials and a visual inspection of alterations were carried out and, finally, a deterioration diagnosis was determined. After chemical characterization, two lithotypes have been identified in the construction of the building: one from Puerto de Santa María and one from Jerez de la Frontera, known as Martelilla. The stone of Puerto de Santa Maria is a calcarenite bio-esparithic with a great variability in the silica:calcium carbonate ratio. It is a very soft and crumbly rock. Martelilla stone is a yellow limestone containing grains of quartz and interstitial granular cement highly recrystallized. Visual analysis revealed that the alteration indicators more common are: the grain disgregation caused by cycles of salt crystallization and dissolution of rising damp, mainly from the ground, and biological alteration such as biofilms formed by algae and mosses and higher plants. Prior to the intervention phase, several conservation treatments have been applied to samples from the quarry of Puerto de Santa Maria, which is the most abundant in the building. The results after accelerated weathering show that the organosilicic products have performed better than acrylic or acrylsiliconic. Results of this study would allow a better selection of treatments according to the stone material and the factors affecting the building.