May a building stand upon gypsum structural walls and pillars? The use of masonry made of gypsum in traditional architecture in Spain

The Rincón of Ademuz (Valencia, Spain) is a region surrounded by mountains, characterized by its endogenous vernacular architecture that, though in bad state of conservation, remains nowadays mainly untouched. Among its peculiarities, it may be pointed the use of gypsum as the only mortar to build up pillars, walls, floors, larders... and even to render the exterior facades, in buildings that may have up to three or four storeys. The local availability of the gypsum and the lesser need of wood to fire the raw material in kilns compared to lime are the main reasons for this generalized use of gypsum in the area. But this does not mean that local gypsum is a poor material. Its versatility, its strength against weather and its constructive and structural performance are not worse than other traditional mortars like lime. In this paper, the authors aim to show the broad spectrum of the use of gypsum in the traditional architecture of the area in all its constructive variants, to deepen into its manufacturing, firing and building processes, to study its chemical composition before and after its transformation under the high temperatures of the kiln, and to throw some light on its exceptional performance.