Characterisation of old azulejos setting mortars: a contribution to the conservation of this type of coatings

One of the most typical Portuguese facades’ coatings is the glazed tile (azulejo) wall coating. Azulejos are in Portuguese history for six centuries, being considered a historical heritage and a mark of Portuguese culture. The setting mortar used in the azulejos application plays an important role for the correct functioning of the entire coating system. Therefore, for correct conservation its study and well detailed characterisation are fundamental.
Within the scope of DB-HERITAGE project (Database of building materials with historical and heritage interest), a deep gathering of data from literature, concerning the characteristics of azulejos’ setting mortars, from the 16th to the 20th centuries, was made. Adding to the existing data, a physical, mechanical, chemical and mineralogical characterisation of a set of azulejos´ setting mortars, from the 16th to the 19th century, from Lisbon and Coimbra cities, was carried out.
The results obtained in the experimental study were analysed and compared with the ones gathered from literature leading to establish useful conclusions for the prescription of future conservation interventions for this type of coating.