Even the details make a difference: problems and solutions regarding interventions on historic masonry cornices

The brick masonry envelope of a historic building may host several protruding elements creating graceful chiaroscuro effects. Windows frames and cornices made of fair-faced bricks protect façades and windows from rainwater and sunlight. They all have a very precise functional role and they have to face and manage natural agents during all their lifespan. Rainwater, fog and snow can bring moisture inward in the wall and favour mould and biological growth. Large overhanging elements can cause problems of rotational stability, which are solved through the affixing of sturdy corbels. Brick masonry forming these elements can be affected by ageing and malfunction, but some design or construction inaccuracies can accelerate these phenomena. The reduction, simplification or the disappearance of such decorated projecting elements in contemporary architecture certainly did not reduce these types of damage. Since knowledge of construction technique and constant correct maintenance works are the natural methodology for the conservation of this architectural element, errors in diagnoses led to incorrect consolidation and maintenance procedures that may lead to unexpected consequences and be the cause of increased surface degradation of the architectural heritage. The aim here is to report the consequences of inaccuracies in design or maintenance of projecting elements, with reference also to the brick facades of one of the most important Baroque buildings in Turin, part of the UNESCO site “Residenze Sabaude” and place of the first Parliament of the Kingdom of Italy.