History of windows glass from invention to mass production
Ancient civilizations held the sun in high reverence, recognizing its vital role in providing light and sustaining life. Throughout history, humans have always sought light within their living spaces to facilitate their daily activities. Initially, natural light was cherished, while the advent of fire brought about the introduction of artificial light as humans grasped its transformative power.
First discovered – Egypt
The glass was first unearthed in Egypt during the Roman occupation, with the earliest signs of human-crafted glass dating back to 4000 BC when it was applied as a glaze for stone beads.
By 100 BC, the art of glass blowing had become well-established, although glass wasn’t widely adopted as a material for windows due to its dense colouration from impurities.
However, by the 1st century AD, the production of colourless glass had begun. The Romans, during their conquest of Britain, introduced the process of glass-making. Nonetheless, it took some time before glass began to be used for windows in that region.
16th century England
In the early times, windows weren’t glazed. Instead, they were left open. In 16th-century England, it was common for windows to be covered with shutters, oiled cloth, paper, or even thin slices of horn.
Glazing, being an expensive process, was a privilege accessible only to the wealthy and was typically reserved for high-status buildings.
The common design involved small glass panes set into a lattice framework of lead strips, a style known as leaded lights.
During the Tudor era, the use of glass became more common, yet it remained a luxury accessible mainly to the affluent and influential.
However, the 17th-century Italian Renaissance brought about significant changes to window designs in England, most notably the introduction of a classic concept involving a square window divided into four quadrants by a mullion and transom. Soon after, the sash window came into existence, featuring a type of glass known as crown glass.
Crown glass, an early form of window glass, got its name from the distinctive method by which it was made: blowing the glass into a hollow globe or ‘crown’.
The crown-shaped glass was then reheated and spun out into a flat disk. It was then cut into appropriate sizes for use. The thinnest and most transparent glass was located at the edge of the disk, while the centre, thicker and more opaque, was used for less expensive windows.
As the 18th century rolled in, the sash window design further evolved, featuring thinner glazing bars and more standardized window sizes. A six-over-six pane arrangement became the most common setup.
Crown glass was first produced in London in 1678. Up until the 19th century, it remained one of the two most common methods for making window glass, the other being a process known as a blown plate.
However, the 19th century brought about changes in window design, shifting away from the simple grid style. Innovations included narrow margins on windows filled with coloured glass and curved glazing bars that echoed Gothic designs. Sash windows increased in size as glazing became more affordable and glass production became more efficient.
The History of Window Glass: Cylinder sheet process
In 1834, a novel cylinder sheet process was developed in Germany and subsequently brought to Britain. This innovation allowed for the production of higher-quality glass in larger sheets and at a significantly lower cost. Consequently, glass became more common in homes, especially since this period coincided with the abolition of the window tax.
The dawn of the 20th century saw a shift from hand-blown to machine-manufactured glass. In 1903, laminated glass was introduced, greatly enhancing public safety by allowing the use of much larger panes or sections of glass.
In addition to its safety benefits, laminated glass eliminated the need for glazing bars, further transforming window design and production.
Windows mass production
The advent of mass production in the 20th century introduced a variety of methods to produce high-quality glass in increasingly larger sizes and volumes.
One notable method is the float process, in which molten glass is made to float on a bed of molten tin. This technique is still extensively used today.
Double glazing, another significant advancement, emerged in the late 20th century.
The evolution of glass continues unabated, with many manufacturers striving to achieve thermal efficiency in lightweight, single-glazed panes.