Fig. 1

Spalling features in an altered molasse sandstone. a Core drilled out of an altered sandstone. Note the spalling crack parallel to the outer surface, at a depth of 2 cm, perpendicular to the bedding made visible by the longitudinal crack (Notre-Dame de Vevey, Switzerland). b Spalling in the Cathedral of Lausanne, Switzerland. c Spalling in Coppet castle, Switzerland, south-east façade. d Fractures parallel to the stone surface (Notre-Dame de Vevey, Switzerland). e Close view at a fracture at the side of a buttress during a restoration campaign in the Cathedral of Lausanne. The length of the stone presented here is around 30 cm, and the fractures running parallel to the surface