History of the Sash Window
Timber windows in England have been around for hundreds of years. The sliding box sash window originates in 17th Century London. It is a common misconception that sash windows were an imported design, but in fact the sash windows you see abroad are exported and you can find them in colonised countries across the world including India, the Caribbean and America.
The design of the sash window comes from a time when streets were narrow and windows jutting out could have touched the building opposite or blocked the path of a thatcher. The “Yorkshire sash” as it is more commonly known is a horizontally sliding window, normally with one of the sashes fixed. This predates the vertical sash window and was a common feature across the country.
The sliding sash window came to the fore after the great fire of London (1666). English Baroque, as the period became known, was responsible for many architectural masterpieces built with sliding sash windows, such as the remodelled Hampton Court (See pictures), Greenwich and Kensington Palaces.
The actual design of the counter balanced window has not been attributed to any one person or any single geographical area. It is commonly accepted that the vertical sliding sash window was probably held open with wooden wedges and then this developed into a counter balanced idea, handmade lead weights held on twine rope. Our fitting teams have come across some of these old weights and straggles of rope whilst removing some very old windows in listed buildings.
The architectural designs of the sash window mainly follow the development of glass. The process of manufacturing glass has been developed and improved over the last 500 years.
The main design of the sash windows are:
- The original multi pane sash window which became popular in the Georgian Period 1714 -1811. This design included the bowed window which was designed to bring in light especially in narrow streets. Other notable features were the intricate glazing bars which held in the brittle handmade crown glass. A lot of the earlier Georgian sash windows had quarter panes to the outside edge of the windows whereas the later Georgian windows had panes which were evenly split. Large panes of glass were too expensive to make hence many smaller panes.
- In 1774 the city of London & Westminster starting to enforce a comprehensive building regulations act. This covered built up areas, stipulating that all windows and doors were recessed backed 4 inches. This was to reduce the risk of fire spreading from building to building. Other earlier acts including parapet walls to rise two and a half feet above the Garrett floor. Building regulations of sorts have been around since the 1100s. Thatched roofs were banned in London in 1212.
- Building regulations were not always implemented, the properties below are late 1790s. Developing areas of this period such as Brighton were not organised and building regulations were not enforced until much later.
Regency or late Georgian 1811-1830 windows were distinctive in their design still retaining the multi paned look but incorporating ornate features and mouldings which was fashionable, especially in Brighton around the Prince Regents Royal Pavilion.
The Victorians 1830-1901 brought with them development and glass technology. Other notable points of this time were the abolishment of the window tax 1696-1851. The window tax had a big impact on period properties as you can see many bricked up windows were made as an architectural feature. However this detail was commonly used in much later properties as a design from pattern books which many developers of this time used. Cylinder plate glass was developed in 1834 was introduced across English towns and cities form the 1850s onward. This enabled the economical manufacturing of large and heavier panes of glass. Rural communities were slow at picking this up and the multi pane “Georgian” windows were common in these areas up until the 1880s.
- Victorian houses are now associated with large single pane windows many with canted rather than bowed bays. Canted or square angled bays were a third of the labour cost of bowed windows. During this period many late Georgian and regency properties had their windows upgraded, a sign of wealth was large windows without glazing bars. To accommodate these heavy single panes of glass the horn or joggle was introduced on the upper sashes. This is a detail you can see in the corner of the sash which is to hide a mortise and tenon joint which slots into each other. Earlier multi pane window were just slotted together but this joint proved to be weak with the weight of the new Cylinder glass.
Edwardian and later (1901) sash windows are noted for their combination of earlier features, mainly the Georgian or ornate top sash over a single panes Victorian sash. This was the last change in sash windows as the cost of labour grew mainly to loss of competent trades men in the wars that followed. Sash windows have never been phased out due to the ongoing repairs carried out on old houses or mock Georgian houses made with inferior sash window designs, including cheap fast grown timber with spring balances.
- Modern replica sash windows, these are double glazed, constructed out of Accoya and finished with microporus paints.
Interested in Sash Window History? Worth a visit – Hampton Court sash windows. Some of the best examples anywhere in the country. Circa late 1600s. This facade was remodelled by Sir Christopher Wren for Queen Anne.
Materials used for traditional timber sash windows.
- Oak was predominantly used for all types of windows up until the the early 1700s. After this, Oak was gradually phased out as main stream material. This would have been due to availability and cost. The various wars and large Navy fleets of this time required thousands of Oaks (Navy Ships would have required the felling and use of hundreds of Oak trees). Building booms of the Georgian period had also increased demand and stripped forests across the country. The result of the higher price of Oak and increased trade across the Baltic hand introduced the use of Redwood (Pine) as the everyday material for Sash Windows. Early Victorian Sash windows are made of a well seasoned close grain Pine, which weathers as well as modern Hardwoods. The later period windows, heading into the the Edwardian era are generally made of a faster grown Pine. Depleted stocks of older, close grain slow grown pine, post the Industrial Revolution of 1840 – 1880 forced the use of younger trees. These had a higher moisture content and are a lot more susceptible to rot.
- Glass has been used in windows for the lat 800 years. Crown glass and cylinder glass are similar and indistinguishable by the untrained eye. Crown glass was used up until the mid 1700s. It is slightly thinner than cylinder glass and has a charm of distortion. We do come across this original glass form time to time if the circumstances of history have allowed its survival. North facing, well maintained properties of the Georgian period may be lucky enough to have the original sash windows and Crown glass. Another point that is often forgotten in modern times is that lower windows often had their panes broken by small stones, thrown up by cart wheels (Horse & Cart). Roads were often made of loose chippings or cobbles. Cylinder glass became the manufacturing process of choice from the early 1800s and then machine made Cylinder glass post 1850s as noted above.
- Sash weights for the use of counter balancing the sash window have not changed much since the early invention of the sliding box sash window. There is not much to develop with a block of metal! However there appearance does differ over time. Again, this was due to local hand made production and then mass production. Original sash weights were made from lead. Lead was easier to work with on a small production with lower melting temperatures and sand moulds, often made in longer lengths then cut to size according to the weight required. Cast Iron weights were cheaper to make, both in labour and materials, but this process had to be done on a more industrial scale. We find original sash weight in windows manufactured up until the 1820s. Later windows are generally counter balanced with cast iron weights.
- An important foot note is that more isolated villages and country houses used the older more traditional methods of the manufacturing of sash windows, right up until the 20th Century. This includes Oak (Grown locally on the large manor estates), Lead weights and early techniques of hand making of Cylinder glass. Mouldings differ also, as these blades were forged locally. In the trade we generally refer to this as “Country made”.
Sash Window Mouldings
Mouldings were used to enhance the look of traditional joinery. This has been the norm for hundreds of years. This peaked around the Regency period, with extravagant designed windows, with intricate glazing bars and moulding patterns.
Thank you for reading. Please feel free to email me if you would like further information on the history of the sash window.
This is original content written from knowledge –
by Pembroke Nash