History of the Sash Window: Part 3

Glass glazing

Throughout the Georgian period (1740 – 1830) the most common form of window glass used for less expensive windows was Crown. Crown was a blown glass with a unique and distinctive look, owing to its subtle concentric rings and ‘bullseye’ centre. Before 1838, plate glass manufacture was too expensive to affect the design of sash windows, but when the cheaper sheet glass was introduced glaziers had more options for creating windows for a more modest budget.  In the decades following the end of the Georgian period, owners of older houses were beginning to remove glazing bars from windows and by the 1850s the principle facades of more expensive villas and terraced houses were fitted with plate glass windows. Glazing bars weren’t completely set aside however, and could still be seen in basement windows, attics and any less visible areas.

Sash window horns

The implementation of larger glass sheets led to a new sash window design development in the addition of horns, essentially a continuation of the style beyond the outer meeting rail joint, creating a mortise-and-tenon joint (a fixture used for thousands of years to connect pieces of wood at an angle of 90°) to afford the structure more strength. Sash window horns were moulded, one of the most typical designs being a variation on the ‘ogee’ moulding (an ogee is an S-shaped curve consisting of two oppositely-curving arcs), though there were many regional variations. Later in the 19th Century, individual builders often stamped their creative style on sash windows by developing their own unique approach to the design.


Sheet glass was common in Victorian Gothic villas and terraces, and by the 1870s the four-pane sash window was the most common window for cheaper terraced houses, though, again, there were regional variations depending on locality. Plate glass was predominantly only used for the more important rooms and the use of glazing bars  were still used for the less visible parts of a house, except for rural areas and the least salubrious properties, where they were employed throughout the period, as were casement windows.

Glazing bars back in favour

 The influence of architects such as Philip Webb and Norman Shaw in the 1880s, and the Queen Anne Revival style, led to the return of glazing bars for more expensive properties, which often imitated Queen Anne windows with Victorian modifications, such as sash window horns. A popular design, particularly in the 1880s and 1890s, had glazing bars in the upper sash, with the lower sash a single pane or divided vertically into two. There were several permutations on this theme, continuing the trend for unique and varied sash window styles. By the turn of the century some tremendously elaborate sash windows were made – often designed to sit behind Tudor-style mullions, appearing like casements.

Furthermore, there were several patents submitted for sash windows in the later 19th Century. One such patent can be seen in certain hotels and public buildings: a device which allowed the sash to pivot inwards to facilitate easier cleaning and maintenance.

Victorian & Edwardian eras

Late Victorian and Edwardian villas introduced the practice of running an intricate moulded cornice across the meeting rail, typically mounted on the box frame with the sash operating behind, though sometimes the meeting rail itself was curved or had a small dental cornice, as can be seen in some districts in North London.

By the turn of the century, whilst the sash was still the dominant style, lead casement windows were starting 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, demonstrating how window designs are susceptible to trends as with anything else design-related.

1920s – 1940s

During the twenties and thirties, sash cords started to be substituted for chains in the sash windows of many domestic properties. Chains had been used for large plate-glass windows in the 19th Century, but not generally in houses. After the First World War, despite still featuring in larger neo-Georgian style houses, the revival of vernacular styles and the popularity of the mock-Tudor style led to widespread  abandoning of sashes in favour of wood and steel casements.

Following the Second World War, the sash window was probably as scarce as it had been throughout its now-long history. The steel spiral balance began to replace the pulley and weights, which were deemed both too costly and old hat. 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.

1950s -1980s

By the 1950s, the steel window and mass-produced casements became almost universal, except for the odd sash window in revived Georgian properties. By the later 1960s, it became common to replace any remaining sash windows, particularly in smaller terraced houses, with plate-glass, often with louvered vents at the top, thus sadly disfiguring many otherwise-grand Victorian houses. By the mid 1970s, the aluminium window, with its sealed glass units, began to supersede internal double glazing, and window replacement commenced on an unprecedented scale in the UK, something which only increased in the 1980s. Replacing the whole frame – not just the sash – became the norm. Hardwood frames were combined with aluminium double-glazed units; a shambles, aesthetically. Many an 18th and 19th Century house has been ruined by such alterations.


On the streets of the United Kingdom today, we have a sad state of affairs in that original windows of classic period houses have been replaced left right and centre.  In fact, in most areas we see around 75% replacement of sash windows with lesser or period-inappropriate designs. There is hope, however. With the conservation movement continuing to gain momentum and growing public interest in the design and aesthetic value of Georgian and Victorian houses (and general appreciation of master craftsmanship and traditional methods), people have become aware of the damage done by such culturally-negligent replacement practices, and there is a growing number of property owners who are keen to restore sash windows to their former glory.

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