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The History of the Sash Window


The Sash Windows, with their subtle proportions and elegance, were one of the most important visual elements in buildings of the 18th and 19th Centuries. By Victorian times, they were the most popular form of window. In the past fifty or so years, however, their popularity declined. But with the growth of a more enlightened attitude towards conservation and growing appreciation of the craftsmanship and design that went into everyday buildings of the 18th and 19th Centuries, sash windows once more enjoy a revival.

People appreciate their aesthetic and functional contribution to the house, and they are now restoring and reinstating sash windows that were removed in less enlightened days.


The origins of the sash windows have been the subject of much investigation and speculation. Until recently, the general opinion tended to be that sash windows were invented in Holland in the late 17th Century. Recently, however, valuable research work undertaken by Dr Hinte Louw, of the University of Newcastle Upon Tyne, suggests that sash windows could have been invented earlier in the 17th Century in England. Another school of thought suggest that sash windows originated in France and spread to England via Holland.

The word “sash”, derived from the French “chassis” , means frame. But, however it originated, sash windows are as traditionally British as roast beef, and have become synonymous with all kinds of Georgian, Victorian and Edwardian houses.

Early Use

Early Use 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 sash windows very fasionable in both old and new buildings, and it immediately became something of a status symbol. Sash windows were ideally suited to Palladio’s “perfect canons of proportion”, that were practised in England by Inigo Jones.

The development of sash windows was timely, because it had enormous aesthetic and practical superiority over the older casement windows.

The wrought-iron hinged metal casement, with its mullions and lead cames, was not only dark and draughty, but the leaded casement restricted the use of larger sheets of glass, owing to the relative weakness of the lead. Casement windows, when open, detracted from the facade rather than enhancing it, whilst the new sash windows were enhancing with their white frameworks and larger sheets of glass. The crown glass in these early sash windows created beautiful reflections that could not be matched by the small panes of earlier windows.

People who could afford the new sash windows ruthlessly cut out their leaded-light windows, which explains why so many larger 16th and 17th Century houses have early 18th Century windows. This fashionable modernisation was often lavished only on the principal facades, and early casement windows often survived on the less prominent facades. The earliest sash windows had thick glazing bars to the sashes, which were usually constructed of oak, the weight box being set almost flush with the outer wall.


Window Tax

At the time when the window tax was introduced in 1696, window design was undergoing the most significant change, both aesthetically and functionally, in the history of architecture in England. The status value of sash windows was increased by the window tax. In 1746, a heavy excise duty on glass was introduced, and it was increased over the years until the tax was abolished in 1861. During the interval, as is well-known, many sash windows were blocked. This process, however, is often confused with the use of dummy windows to maintain proportions.


Buildings Act

Buildings Act Two Building Acts affected the appearance of sash windows in London. They were imposed because exposed sash boxes were seen as a fire risk.

The 1709 Act stated that sash windows had to be recessed 4″ back from the outer brick-work or masonry. The 1774 Act required the sash windows box frame to be set behind the brickwork, so that only about an inch of the sash box was visible from the outside.

This, however, is not a dating guide. These Acts applied to London, but were not generally followed, as can be seen in many 18th and 19th Century towns. The speed with which changes took place also varied between areas.


Early Development

Early Development Early in the 18th Century, what is thought of as the classic glazing pattern of the Georgian window developed. This design, six panes over six panes, remained in use even after the advent of larger panes in the 19th Century, particularly in cheaper properties.

At this point it is worth mentioning something about the construction of the window. In buildings such as Hampton Court Palace, sash windows frame were constructed in a similar way to today, built out of sections. However a method that was widely used well into the 1720′s, and probably later, was to make sash windows frame out of solid sections pegged together in the same way as casement windows were, with the style hollowed out to allow enough room for one sash weight on each side. Usually only the lower sash was made to operate on these early windows.

Another interesting mechanism, which can often be used as a useful dating guide, is the sash pulley itself, i.e. the wheel which the cord passes over, and which is attached to the sash weight. In early sash windows, this wheel was of brass where funds permitted, or boxwood or oak. The wheel was set either with a pin directly into the frame, or into a separate wooden block, to facilitate removal and repair. The construction of the pulley case varied considerably and these early sash windows were often quite simple, compared with the exquisite joinery of the later Georgian period.


Later Improvements

Later Improvements As the 18th Century progressed, the construction of sash windows improved. The most important development was that glazing bars became steadily thinner as the century progressed. Later in the 18th Century, larger panes of glass became available and the extremely elegant glazing bars, that we admire so much today, became general. In more expensive work, these bars were sometimes constructed of iron or brass, often painted to appear like wood.

Window construction improved also, and by the end of the 18th Century the basic construction, that is familiar today, has been developed. By the 1750′s sash pulleys in more expensive work were set into iron frames with a solid brass face-plate. The grooves in which the lower sash moved were not painted – a practice that went on to the 1830′s. It was a sensible idea, because the sashes would not jam or stick. In some areas the outer channel of the pulley style is still left unpainted.

Later in the Century, cast-iron and brass sash pulleys superseded the earlier types, and a multitude of other developments in sash-pulley design burgeoned throughout the 19th Century – illustrating the care, thought and invention, that went into the improvement of sash windows.

Although early sash windows were mainly constructed of oak, imported Baltic softwoods became widely used for sash windows. However oak and, later, mahogany, continued to be used up until recent times. In most work, oak was used for window sills, the rest of the window being constructed of soft wood, which remained the common practice from the mid-18th Century until the Second World War.

Among the numerous types of 18th Century sash windows, the tripartite or Venetian was an imposing example. It often consisted of a central sash with two side lights, one pane wide. The side lights were often fixed, with the sash cord running over their heads from the central sash into the weight boxes. A less common type was made so that all three sashes could operate, with wider mullions for the weight boxes.

Throughout the late 18th and early 19th Centuries, sash windows were used in the most complicated situations, often built to appear as casements in Gothic and Tudor Revivals. These revived designs often involved elaborate construction with moulded mullions and even concealed pulleys and weights.

In the early 19th Century, the use of margin lights became very popular and, combined with cast-iron balconies, created a delicate and extremely elegant feature now termed “Regency”, although this style continued into the 1840′s.

Throughout the ensuing three decades, sash windows was employed in Italinate villas and terraces springing up in fasionable areas, and in Victorian Gothic villas, with much plate-glass on the principal elevations.


Glass & Glazing

The most common form of glass throughout the Georgian period was Crown glass. This was made by blowing, with a central bull’s-eye, and had a unique sparkle. Plate-glass manufacture was too expensive to affect the design of sash windows until 1838, when sheet glass, a cheaper form, was introduced. At first, the use of the plate-glass was confined to the upper end of the market and, by the 1840′s, owners of older houses were beginning to remove glazing bars from windows to the principal facades. By the 1850′s, more expensive villas and terraced houses were built with plate-glass windows to front facades. Glazing bars were still used in basements, attics and on less important elevations.

The use of larger sheets of glass led to the introduction of horns on sash windows, which were basically a continuation of the style beyond the outer meeting-rail joint, providing a mortice-and-tenon joint, to give added strength to the meeting rails. Sash windows horns were moulded, one of the more usual designs being a variation of the ogee moulding. But this depended on the builder and the locality, and there were many regional variations. Later in the 19th Century, builders often adopted their own in-house style, as may be seen in many late 19th Century developments.

The most widely used design were four-paned sash windows. Sheet glass was common in Victorian Gothic villas and terraces, and by the 1870′s the four paned sash was the standard for cheaper terraced houses, although there were regional variations. As a general rule, plate-glass was used only for the more important rooms. The use of glazing-bars, and the social hierarchy of glazing, depended on the builder and the area. In rural parts and poorer properties, glazing bars were employed throughout the period, as were casement windows.

In the 1870′s and 1880′s the influence of architects such as Philip Webb and Norman Shaw, and the Queen Anne Revival style, led to the return of glazing bars, which often imitated Queen Anne windows with Victorian modifications, such as sash windows horns. A popular design, particularly in the 1880′s and 1890′s, had glazing bars in the upper sash,with the lower sash a single pane or divided vertically into two. There were many variations on this theme.

Many patents were taken out for sash windows in the later 19th Century, One of these may be seen in hotels and public buildings in particular. This was a device which allowed the sash to pivot inwards to facilitate cleaning. The varieties were too numerous to mention here, but by the end of the 19th Century some extremely elaborate sash windows were made – often designed to sit behind Tudor-style mullions, and appear like casements.


Victorian & Edwardian

A practice often seen in late Victorian and Edwardian villas was to run an elaborate moulded cornice or transom across the meeting rail. This was usually mounted on the box frame, with the sash operating behind it. Sometimes, however, the meeting rail itself had a miniature dental cornice, or was curved, as may be seen in districts such as Muswell Hill, North London. In the same districts can be seen elaborate multi-curved sashes.

By the turn of the Century, the sash was the most widely-used window. However, the use of steel windows and casements had grown with Revivalist styles, especially the Queen Anne, as may be seen in buildings designed by Norman Shaw and other architects, and the lead casement was beginning to make a come-back.

The growth in use of the casement increased during the Edwardian period, and by 1910 many houses were built with timber casements, with sash windows relegated to less important elevations.

After the First World War, although sash windows were still used in larger houses in the neo-Georgian style, the revival of vernacular styles, that took place before 1914 through architects such as Lutyens and Voysey, and the great popularity of the mock-Tudor style, led to the general adoption of wood and steel casements. (The latter were made in standard sizes by many firms, the two best-known being Henry Hope of Birmingham and Crittall of Braintree).

The construction of sash windows involved more sophisticated techniques and mouldings, with added labour costs, and this was probably one of the major reasons why mass-produced steel and timber windows were adopted generally after the First World War, particularly for housing estates. Some councils’ building estates in the neo-Georgian style continued to use sash windows.


Twenties & Thirties

During the twenties and thirties, chains often replaced sash cords in the domestic setting. Chains had been employed for large plate-glass windows in the 19th Century, but were then rare in houses. By 1939, 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-fasioned. Steel windows and mass-produced casements became universal, and the sash was considered “old-fasioned”, although it was to be seen in revived Georgian settings.

By the 1950′s, many owners of older houses were replacing sash windows with up-to-date steel casements that were hinged for easy cleaning. By the later 1960′s, it became common to replace sash windows, particularly in smaller terraced houses, with plate-glass, often with louvered vents at the top, thus disfiguring many splendid Victorian houses. By the mid 1970′s the aluminium window, with its sealed glass unit, began to supersede the idea of internal double glazing, and window replacement began on a scale never before seen in this country. By the early 1980′s, this process increased. It became quite usual, not only for the actual sash to be replaced, but for the whole frame to be replaced by a hardwood frame, and aluminium double-glazed units – totally unsuitable aesthetically for an older house. Many 18th and 19th Century houses have been ruined aesthetically by such alterations.



Today Now, in the twenty first century, it is possible to walk down Victorian streets and see a selection of replacement windows dating from 1950′s, 1960′s, 1970′s and 1980′s. It can be alarming to see that as many as three-quarters of the original sash windows have been lost. Fortunately, however, with the growth of the conservation movement, and public interest in and appreciation of the craftsmanship, design and visual worth of Georgian and Victorian houses, people have become aware of the damage done by such insensitive replacements, and are now keen to reinstate their lost windows.

Traditional craftsmanship is, thankfully, once again in demand, and The Original Box Sash Windows Company of Windsor is an example of a company enjoying considerable success in the construction and installation of sash windows, that are both aesthetically pleasing and immensely practical.