Glass in windows
When glass was discovered in Roman-occupied Egypt,it wasn't only used for decoration but to form small panes that were then set into those openingsWhen Rome occupied Britain,they brought glass making with them.
To make window glass,the Romans started with a long balloon of blown glass.They cut off the ends and split the resulting cylinder into two.The half cylinder would be placed on an iron plate and flatten -ed.This manufacturing process meant that openings were limited to a small size,but that changed in the 17th century when,in England,a process for making large panes of glass was discovered.
Unfortunately,this breakthrough didn't benefit the English when it came to windows in their homes because, in 1696, William III introduced a "window tax".People were required to pay between two and eight shillings a year,depending upon the number of windows in their houses,and many bricked over their windows in order to avoid the charge.(William's window tax is where the term"daylight rpbbery" originates from.)The tax remained in place for 156 years,with the levy-free window allowance going from 10 to six and then to eight.The tax was finally repealed in 1851.
Polished plate glass was introduced to Britain in the late 18th century;however,the production proc -ess was so expensive that it was only used for windows in the best rooms of larger,more expensive homes.
When,in 1834, a cylinder sheet process for glass-making was imported from Germany,Britain was ab -le to produce higher quality glass in larger sheets far less expensively than previously-used methods. That combined with the withdrawal of the window tax meant that the price of glass was greatly reduc -ed and more people could afford to have windows in their homes.This included opaque glass which, by 1888,was primarily patterned and produced by machine rolling.
In 1903,laminated glass was introduced,which greatly increased safety and allowed for wider use of much larger panes of glass.Laminated glass could also be glazed as a single sheet,without the need for glazing bars.
The 20th century brought a plethora of new techniques for mass production, which led to cheaper ways to consistently produce higherquality glass in increasingly larger sizes.The glazing technique introduced,and still widely used today, was the float process – where molten glass floats on a bed of molten tin whilst the top surface is polished usingpressurised nitrogen.Double glazing was introduced in the late 20th century as means to improve energy efficiency in homes.
