How Sash Windows Have Evolved Over Time
Social, cultural and industrial history can all be traced through the historical development of the sash window. As the availability of wood, glass, and metals has changed and the ability of builders to work with these has been improved upon, the shape of sash windows has altered with the times. Where they are still intact, sash windows tell us much about a building and its history.
The concept of the sash window originates in Europe in the middle ages when sliding, glassless panels were used to cover windows. It was not until the sixteenth century that glass came to be used and a balancing mechanism was developed that enabled vertical sliding sashes to replace their horizontal forerunners.
It was in the seventeenth century that this particular design of window made its way to Britain and began to be used in the homes of those who could pay the high prices involved. To have a sash window became a status symbol that said a lot about the size of the owner’s bank account.
Originally, the windows were produced with numerous small panes of glass, held in place by crossbars and they were particularly heavy items. Improvements in the glass making industry later enabled wider panes to be made from a single sheet. A tendency to use a couple of large sheets instead of multiple small ones emerged and became more financially viable after the taxation of glass ceased in the mid eighteen hundreds.
The basic appearance of the sash window remained the same through most of the 18th and early 19th centuries with the most popular form being the “six over six” window. This featured two sliding frames, one over the other, and containing six panes of glass each . In the early 1700s, designers favoured an arch over the top of the light, but this reverted to the rectangular shape in the latter part of the era. Hidden boxes recessed into the window frame to hold the mechanism were developed later without altering the outward appearance of the window.
In the early eighteen hundreds a distinctive form of sash window emerged for a period. The traditional six panes of glass were altered in shape and size to give a large pane in the middle with lesser panes or sidelights on either side and above or below. These windows demonstrated to an even greater degree the high status of the purchaser.
In the later eighteen hundreds such large panes of glass were being increasingly used that it was necessary to extend the outer edges of the supporting frames to secure them. These extended “horns” can be still be seen on many sashes from this era. Some architects of the late nineteenth century also reverted to using smaller panes of glass in conscious emulation of more historical designs.
Less regulation and wider availability of affordable materials mean that, in the last 200 years, the design of sash windows has been unrestricted by such considerations and a variety of styles have continued to be built, emulating some of the popular forms of the past according to taste.
Original windows in a historic building can give a number of clues about the date of origin and even the social class of the earliest inhabitants. The historical development of the sash window reflects the social and industrial history of the land.