Freixo palace: Rehabilitation of decorative gypsum plasters

摘要

Gypsum plasters, as decorative elements in Mediterranean dwelling buildings, are part of their architectural heritage. Because they were somehow "democratized", their use was not only rather common but also connected with a certain architectonic style that was vilified a few decades afterwards as too intricate and fatuous. More recently, the public and private entities that own or supervise the buildings in which gypsum plasters were profusely used woke up to the obvious need of rehabilitating these very striking features of the inner rooms and entrances. One such example is the intervention made at the XVIII century Freixo palace in Porto, Portugal. After a brief introduction and characterization of the building, the paper describes the general state of conservation of the gypsum plasters within it, focusing on the following anomalies: water entrance, biological colonisations, salts, chromatic changes, vandalism and abandon, cracking, and incorrect restoration. The works of conservation and rehabilitation of the building are then described in some detail. The most appropriate strategy to tackle the problem is discussed and the actions actually taken (preliminary operations, elimination of biological contaminations, consolidations, stabilization and consolidation of ceilings, removal of incompatible mortars, reinstatement of decorative elements and filling of gaps, cleaning of surfaces, and rehabilitation of paintings) are justified. Some final comments are put forward.