Flat Glass

Mario Moretti

The need to shield a window with transparent material, was the reason that led to the production of glass sheets, starting right back from the Roman era. Sheets of small dimensions, no larger than 50x80 cm, were produced by casting the glass on a plate and pulling the end with pliers or other tools, until the whole mould was filled to the edges. These sheets can be easily recognised by the irregularities of the thickness, which is thin in the centre an often rounded at the edges. The main push towards the production of sheets probably came from the widespread use of polychrome stained-glass windows, connected to the use of lead, from the 11th century, in the construction of Gothic cathedrals in Europe. But it was from the 17th century that more sophisticated and less costly methods were developed to produce increasingly larger sheets with uniform consistent thickness. The sheets found wide-scale use in the civil building field too, up to our times with the development of structural facades, in which whole sides of skyscrapers and commercial buildings are made in glass and the use of glass in forms of transport.
After the use of glass casting, other techniques which followed were the disc system, the cylinder one, the casting between rollers and, in 1900, with the advent of continuous production, first came pulled glass and then, from the beginning of the 60s, the float technique, which has completely replaced all other technologies.