The use of thin sheets of malleable metals to solve the problem of waterproofing roofs is a deep-rooted, centuries-old practice in western construction, especially in countries of plenty of rain. Because they are so easy to bend and fold, building tradition has over the centuries developed complex and efficient joints based on the geometry and the overlapping of various sheets. This provides much better protection against the infiltration of water than the traditional roofs of small overlapping pieces, such as tiles of slate or scales of wood.
The use of zinc for waterproofing purposes is recent, however, compared with other metals. Although in more recent times zinc has been the metal most identified with this construction technique, it was not used as a cladding material until two hundred years ago. Up to then the materials commonly used for this end were copper and lead, which are like zinc in their grayish color and their practically homogeneous matte patina....
