Earth Masonries in the Medieval Grange of Cuna - Siena (Italy)

The Grange of Cuna was the administrative and storage centre of the bigger farm of Santa Maria della Scala Hospital in Siena. Built from the early 14th century, the Grange is characterized by continuous development of the building until the second half of the 18th century. For his extraordinary state of preservation, its size and the internal organization of individual buildings, it is notable for being one of the finest and rare examples of fortified farm in the context of Italian and European Middle Ages. At present a plan of restoration is under preparation, for whose completion many studies have been performed. The architectural survey, thanks to the accuracy of laser scanner technology added to a critical interpretation and data processing, represented the first knowledge of spatial and geometrical information and also gave a model useful to identify structural instabilities and deformations in order to direct the diagnostic phase. The stratigraphic investigations extended over the entire architectural complex made it possible to distinguish the historical constructive phases of the farm. Among the different masonries, fired brick masonries with earthen bedding mortars have been found in the original medieval nucleus, while rammed earth masonries plastered with lime mortar are present in some late medieval or post-medieval additions. Specific “in situ” investigations such as sonic and double flat jack tests were carried out on each masonry typology. Samples from the masonries with earthen bedding mortar and rammed earth were characterized in their mineralogical and petrographic features. This paper represents a first indication and reports a thorough investigation of walls built with earthy materials in this important medieval complex in Tuscany.