Quantification of salts in extracts from bricks ("Wall of bricks" at the Wawel Castle in Cracow)

The concentration of soluble salts in the retaining wall of the Wawel Castl e was estimated. This wall bears the pressure of a steep, earthen slope of medieval fortifications. The analyses have shown that the samples contain m ainly sulphate, nitrate, chloride, calcium, sodium and potassium. The conce ntration of the ions increases distinctly from the inner side of the wall t oward the outer, exposed part. Due to the specific position of the wall and in contrast to most other buildings, water penetrates the retaining wall f rom the side abutting the scarp, while capillary suction from the foundatio ns is of minor importance.