History of the Sash Window: Part 2

Window tax

A window tax was collected in England from 1696 through to its abolition in 1861. The time of its introduction coincided with the most significant functional and aesthetic change in window design in English architectural history. The tax only served to increase the social currency of the sash window, which was by now very much a status symbol.

A photo about Sash window tax in 1746


A heavy excise duty on glass was introduced in 1746, increasing incrementally until the window tax was finally abolished, which gave rise to the curious (but understandable) phenomena of less well-off households blocking out their sash windows during the period. So in many instances over the years, to restore sash windows one had to first unblock them of bricks or boards. NOTE: this process of blocking is not to be confused with ‘dummy’ windows being employed by architects in order to maintain proportions.

Buildings Acts of 1709 and 1774

Two acts of parliament directly targeted sash windows in London in the 18th century. They were imposed because exposed sash boxes were deemed a fire risk.

The 1709 Buildings Act stated that sash windows had to be recessed 4 inches back from the outer masonry or brick-work, whilst The 1774 Buildings Act required the box frame to be set behind the brickwork so that only about an inch of the sash window box was visible from the outside. Whilst the specified changes were implemented nationally in many properties, gradually over time, they were not generally followed (even in London) as can be seen in many 18th and 19th Century towns in England.

Early Development

At the beginning of the 18th Century, the 12-pane window was developed; a classic design widely considered to be the archetypal Georgian window. Even after the arrival of larger panes in the 19th Century, the six-panes-over-six-panes design remained in use, principally in properties of lower worth.

Beautiful picture of the sash windows at Hampton Court


In buildings such as London’s famous Hampton Court Palace (which wasn’t officially finished until 1694, building having commenced way back in 1541), sash window frames were constructed in sections, in a similar way to today. One method that was widely employed was to create the sash window frames in the same way as casement windows, with solid sections pegged together, hollowed out on each side to allow enough room for the sash weights. Note: Usually only the lower sash was made to operate on these early windows. Mechanisms such as the sash weights can often be used to indicate the era in which the sash windows were made.

The sash pulley wheel itself is another useful indicator. In early sash windows, the wheels were brass (finances permitting), boxwood or oak. The wheel was set either with a pin directly into the frame, or into a separate wooden block, to allow for removal and sash window repairs. The build of the pulley case varied immensely and these early period sash windows were typically simple in comparison to the fine joinery exemplative of the later Georgian period.

Later developments

Moving further into the 1700’s, the techniques used for constructing sash windows saw some key improvements. Most pivotally, the glazing bars were made to be thinner. By the latter half of the 18th century, larger panes of glass became readily available and the elegant glazing bars we see and admire today became more popular.

For some of the more prestigious and well funded projects, these glazing bars were brass and/or iron, such as iron frames with a solid brass face-plate, and painting them to appear like wood wasn’t uncommon. Furthermore, cast-iron and brass sash pulleys superseded the earlier versions.  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.

19th Century Sash Window development

A myriad of developments in sash-pulley design proliferated throughout the 19th Century, the care and innovation being indicative of the long-felt passion for the sash window. The use of margin lights also became popular in the early 19th century and, when complementing cast-iron balconies, created an elegant feature widely referred to as ‘Regency’, though this style continued into the 1840’s, two decades after the ‘official’ end of the Regency period.

Whilst early sash windows were predominantly of oak construction, softwoods of the Baltic regions also became widely used in the 19th century. Oak continued to be used up until recently, as did mahogany (which came in later). Oak was mostly used for sills, with softwood making up the rest of the window, a practice that remained common until World War II.

Throughout the late 18th and early 19th Centuries, sash windows were 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 Part 3: Glass & Glazing, The Victorian & Edwardian Periods, the 1920s-30s and Sash Windows Today

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