The Manciano Sandstone in Contemporary Architecture: Conservation Aspects in Florence

The use of stone as a building material or ornamental element has a long tradition favoured by several factors such as the availability and ease of quarrying the material in places not far from the city. Until the beginning of the 20th century, stone was the builders’preferred material. During the first half of the 20th century, this supremacy began to wane due to the complex cultural, social, and material transformations that affected architecture. The outcome of these transformations was almost always associated with the rise of the structural frame and modern materials such as steel, concrete, and glass. Today, cladding is the field in which stone materials are most widely used, with the development of new techniques for on-site application, capable to give the stone facing characteristics and opportunities for use that were unattainable before. New extraction and production technologies also allow the use of stone materials that were once difficult to use. Among these, in contemporary Italian architecture, a stone, the Manciano sandstone, marketed under the name of Pietra Dorata®, Pietra Dorata Toscana and Pietra di Santafiora is having great success. The purpose of this work is to examine, in relation to conservation aspects, the use of this sandstone in the city of Florence, where other sandstones have historically been used both in historic buildings and in claddings and ornamental works. Indeed, there are numerous examples of new constructions in Florence that have used Manciano sandstone as a cladding material over the last thirty years or so. Even for a relatively short period of exposure to atmospheric agents, decay phenomena can be observed that are essentially due to the type of installation or to other anthropic factors.