History of the Box Sash Window

During the mid 1600s, improved availability of glass and changing trends in architecture, gave way to a new form of window called the vertical slider – or sash window. The word "sash", derived from the French "chassis" , means frame. But, however it originated, the sash window is as traditionally British as roast beef, and has become synonymous with all kinds of Georgian, Victorian and Edwardian houses. The earliest-known use of sash windows in this country was in the later part of the 17th Century, at Chatsworth (c1676-1680), Ham House, Hampton Court Palace and Kensington Palace. Royal patronage, and its adoption by Wren, made the sash window very fashionable in both old and new buildings, and it immediately became something of a status symbol. The development of the sash window was much needed a the time as it was a drastic improvement of the older casement style windows in that it was lighter and more practical to use and was far more elegant to look at.

Before the Great Fire of London Windows initially were positioned flush with the front face of a building. This style can still be seen, mainly in the countryside. An analysis of the great fire showed that exposed timber was a major contribution to the spread of the fire. The London Building act of 1709 decreed that all windows be set 4" back from the outer brick-work or masonry. In 1774, to further reduce the risk of fire, the box containing the cord and weight mechanism, previously exposed, was required to be set behind the masonry and this is the most commonly seen today.

Early in the 18th Century, the standard glazing pattern of the Georgian window developed. This design, six panes over six panes, remained in use even after the arrival of larger panes of glass in the 19th Century.

Originally constructed of Oak or Mahogany, as stocks began to run out in the mid 18th Century, Sash windows were increasingly made from imported softwoods from the Baltics, such as Pine. Today all new or replacement Sash windows are constructed from Pine.?During the twenties and thirties the use of sash windows was confined largely to neo-Georgian buildings, particularly post offices, banks, public houses and local authority housing estates.

After the Second World War, the sash window was probably at its lowest level of popularity. The steel spiral balance began to replace the pulley and weights, which were considered expensive to make, and old-fashioned. Steel windows and mass-produced casements became universal, and the sash was considered old-fashioned.

During the late 1950’s many older properties were having their sash windows replaced with steel casements with hinges. This made them easier to clean but more clumsy than their predecessors. The six paned Georgian style windows were also largely replaced by single panes during the 60’ and by the 70’s, sealed glass units with aluminum casings were extremely popular.

Today, almost three quarters of the country’s original Sash Box Windows have been lost and many period Georgian or Victorian houses have been spoilt by insensitive replacements. The Swathe of UPVC double glazing installations in the 80’s and 90’s have added greatly to this problem. However, people are now starting to appreciate again the beauty of traditional windows and their value to their property. Home owners are increasingly choosing to restore their existing Sash box windows or have replicas produced, rather than opting for plastic. Increasingly sophisticated draft proofing systems and double glazed Sash windows are now available which make the switch to PVC less attractive.

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