ORIGINAL PAPER Refinement of categorization and scaling of weathering-related damage to natural stone: case study on oolitic limestone from El-Shatbi Tombs (Egypt) G. M. E. Kamh 1 • S. Koltuk 2 • Hosam Ismael 3 Received: 16 December 2014 / Accepted: 19 September 2016 / Published online: 14 November 2016 Ó Springer-Verlag Berlin Heidelberg 2016 Abstract Natural rocks, as well as artificial building materials, in coastal regions are subject to severe attack by salts, primarily from sea spray, acid rain and/or domestic water in industrial and highly populated cities. As the oolitic limestone is the main rock through which the Greco- Roman sites had been excavated, then, the main aims of the current study are to define the damage category (DC) for the weathered oolitic limestone bedrock at coastal regions, with the Greco-Roman El-Shatbi Tombs serving as a case study. Additionally, it aims to modify the DC scale of Fitzner and Heinrichs (The Karolinum Press, pp. 11–56, 2002) to be applicable for defining the damage categories for a given archaeological site where the existing scale isn’t based on any numerical limitations to previously define the DC of a given archaeological site. Detailed field investi- gations including photo-documentation, measurement of the dimensions of these weathering forms and considera- tion of the wall side orientation to sea spray at El-Shatbi Tombs have been used in tandem with the modified dam- age category scale to assess the damage category at these tombs. The net result of processing the field data indicated very severe damage at this site. The laboratory analysis for the small rock samples collected at El-Shatbi Tombs indicated that salts act within the pores of this limestone, particularly in 0.01–0.1-lm pores, at this semi-arid region. Keywords Oolitic limestone  Weathering study  Damage category scale Introduction Weathering processes act on all sub-aerial materials with rates and intensities determined by many parameters, including the type of material and its weathering suscep- tibility, the number and intensity of the weathering cycles, and the specific processes prevailing at a given area (Takahashi et al. 1994; Kamh 2009a, b). The wall side orientation, tilting angle from vertical, rock surface roughness, and rock grain size affect the rock’s weathering susceptibility (Attewell and Taylor 1990; Vendrell et al. 1996; Kamh and Azzam 2008). The rock and pore prop- erties control the transport of salt solutions through the rock, as well as the rock’s susceptibility to weathering, particularly to salts (McGreevy 1996; Flatt 2002; To¨ro¨k and Prˇikryl 2010; Yu and Oguchi 2010). The damage category [as indicated by the Fitzner and Heinrichs (2002) classification] starting from zero for buildings with no damage (i.e., the stone surface doesn’t present any damage affecting its inscriptions and/or paints) to category 5 for buildings with very severe damage (i.e., totally damaged including its original historical inscriptions and/or paints). Sea spray is one of the most prominent salt sources in coastal regions, affecting both recent and ancient structures as well as rock outcrops (Smith et al. 1994). Chloride and sulphate salts in sea spray physically disintegrate (through crystallization and/or hydration-dehydration pressure) the rocks’ fabric, especially sedimentary rocks, e.g., sandstone & G. M. E. Kamh g_kamh2000@yahoo.com Hosam Ismael hosam.ismael@artnv.au.edu.eg 1 Geology Dept., Fac. of Sci., Menoufiya Univ, Shebin Al-Kom, Egypt 2 LIH, RWTH Aachen Univ, Aachen, Germany 3 Geography and GIS Dept., Fac. of Arts, Assiut Univ., New Valley Branch, Assiut, Egypt 123 Bull Eng Geol Environ (2017) 76:39–57 DOI 10.1007/s10064-016-0946-7