Box sash window history
The origins of the sash window has been under a lot of investigation. Until recently the general perspective were that the sash window was invented in Holland in the late 17th century. However recently in the research undertaken by Dr Hinte Louw, suggests that box sash windows could have been invented in approximately 1670 ad in Ham house south of Richmond in London.
The yorkshire sash
One of the first examples of a sash window was the 'Yorkshire sash' which had two panes and would slide horizontally. As time went by we could only imagine that they designed the sash window to be counter balanced and to slide vertically.
Originally molten glass was spun into a disc where small panes were cut. These were then glazed as 'Georgian panes' when the sashes were glazed in 6 panes or more as glass was exspensive to manufacture and only available in small panes. Also glazing bars which had been weighty and broad in the past 17th century were now narrow and elegant. At the late 18th century bigger panes were bieng made from cylender glass allowing larger panes rather then the crown glass method of manufacturing. By the mid 19th century numerous past multi-paned windows were being replaced with 4 paned windows. During the late 19th century glass production had evolved to produce much larger panes. This allowed sashes to be glazed as one pane.