Is gypsum external rendering possible? The use of gypsum mortar for rendering historic façades of Valencia's city

Abstract

[EN] Valencia is a city located in the East of Spain by the Mediterranean Sea. It has a huge historic centre with ancient winding streets that contains buildings with a singular architectural heritage. The buildings¿ façades are protected by a traditional external rendering, sometimes in bad state of conservation or modified or substituted in restoration works. The study carried out on historic renderings in Valencia points out the great employment of gypsum mortar or gypsum-lime mortar, among other peculiarities. Gypsum external rendering is one of the many uses for gypsum mortars in Valencia traditional architecture. This fact contradicts the general belief of the exclusive use of lime mortars for rendering a façade. The knowledge of the characteristics of historic mortars will allow us to implement a proper restoration work of architectural heritage with suitable mortars, as it is essential to guarantee the adherence and compatibility of any repair.