Coatings

Since ancient times, buildings and sculptures have sported paint coats and coloured edging. They served (and still serve) as design elements and also as a protective and wear-resistant layer. The importance of the protective function, in particular against damaging moisture - has increased in recent times in light of emission-related weathering damage.

The International Charter for the Preservation and Restoration of Monuments and Ensembles’ (Charter of Venice’) from 1964 forms a binding base for handling historical building substances at the international level. It acts as the central implementation instructions for all work connected to monument preservation and also defines the requirements made of the building materials that are used. It recommends only using modern preparation and construction methods to secure a monument, if the traditional methods are insufficient and if the efficiency of the modern preservation and construction methods have been scientifically verified and tested in practice (Art. 10).

When applied to the building materials and preservation of structures field, this requirement explains why, when preserving monuments, historically proven binding agents are often preferred over new ‘modern’ binding agents. Also, the Charter of Venice defines requirements for

• reversibility (each measure represents an intervention into the original substances and is therefore to be kept to a minimum and should be ‘repairable’ again as far as possible and/or have the possibility to repeat the preservation intervention again carefully’.)
• and the authenticity (the ‘genuineness’ of the monument should be impaired as little as possible). Frequently, there is a conflict of interests between the preservation of monuments objectives and the technical optimum. In addition, craftsmanship issues related to certain materials and/or binding agents has the potential for conflict.