Building stone as a part of a World Heritage Site: ‘Piedra Pajarilla’ Granite and the city of Salamanca, Spain

Abstract

Abstract Building stone is a significant product in most human communities. While some civilizations paid more attention to the aesthetics of the stone, others focused more on physical properties, especially durability, as well as the ease of transportation to construction sites. These latter issues determined which rocks were exploited, in preference to others, for centuries. Ancient Roman society became expert in constructing durable engineering projects (e.g. roads, bridges and aqueducts). Most of their projects were realized using local granites and most remain in excellent condition today. The historic cores of many European cities need to preserve their integrity, using the original building stone of the city both for new construction and for restoration. A supply of the original material should be preserved in order to avoid use of alternative building stones when restoring old monuments. In Salamanca, a specific unique granite was used to build many of its monuments that are now preserved as part of the UNESCO World Heritage Site. An attempt to preserve this architecture and restore it, when needed, with the original material is the main focus of our paper, as some experiences using other types of rocks have led to unfortunate results.