Transept surfaces

The stone surfaces of the transept featured large and thick deposits of atmospheric particulate matter, which had turned the whole decoration dark grey in colour, to the detriment of the brightness of the original marbles. Moreover, water infiltrations in some areas had caused dirt to be absorbed deep in the substrate, resulting in harder deposits and concretions. The most serious problem in the coffered ceiling and on the group of sculptures was that the pictorial coat had peeled off and broken apart because of the concomitant action of salt efflorescence from water infiltrations.