As for mosaics, also for stained glass windows the main causes of degradation of the glass are the elements that, associated with more aggressive agents found in the air, determine a gradual decay and disintegration of the artistic glass surfaces. In addition, the layers of dirt and soot, by accumulating, cloud the transparency of the glass.
As with mosaics, also with glass care and maintenance is very important.
The outer face of the glass is the part mostly subject to the effects of the weather which create layers of carbonates and sulphates on the surface and then moisture, combining with the carbon dioxide and sulphur of the air, forms acid on the glass which with time attacks the surface penetrating even in depth.
Inside, the glass surface is gradually covered with fine dust, the deposit consists of limestone dust from the masonry and soot from heating and candles. Sulphates resulting from the accumulation of dust are very damaging to parts painted with the Grisaille method. Other problems may arise with crumbling, over time, of the lead bonding grout or of the lead bonding itself because, in the presence of high temperature changes, lead deteriorates losing its characteristics of bonding and seal between the glass pieces, resulting in the glass detaching from its original position.
Novamosaici carries out both maintenance by cleaning the surfaces, and restoration of stained glass, using professional products and equipment.