Zinc has been produced on a large scale only since the 18th century, now thanks to modern forming techniques used in the making of panels and accessories, it is used widely in building for roofing and the cladding of facades. One of the materials patented for this use is the alloy Rheinzink®, made up of electrolytic zinc, combined with copper and titanium. The zinc surface reacts with oxygen from the atmosphere forming a protective patina of zinc oxide, which is then transformed by carbon dioxide from the air into a protective layer of zinc carbonate. This adherent layer which is insoluble in water has a high resistance to corrosion and atmospheric agents. The original grey colour along with the tonal changes that time lends to this material, the effect of light falling on the folds of the surfaces, but above its hard wearing and protective qualities are all factors which have prompted architects to use this material in many recent examples of contemporary architecture.