Some Secrets of Sash Windows

Over the course of many years, I have had occasion to visit and/or study a number of historic buildings. Many of these structures were built prior to or during the English Regency, and thus the design and construction of their windows would have been known during that decade. Most buildings today incorporate windows which are downright dull and boring when compared with the complexity of windows to be found in Regency buildings. In the hope that one or another of these idiosyncratic window treatments might one day feature in a novel with a Regency setting, I offer some of the more interesting here.

And so, secrets of sash windows for the edification Regency authors and their readers …

Before beginning to detail the secrets of sash windows in the Regency, it is important to understand a bit about the history and technology of a sash window. Until the end of the seventeenth century, most windows in English buildings were casement windows. Casement windows are attached to the window frame by hinges at the side. They tended to be small and loose-fitting, letting in little light but many drafts. They were set horizontally to accommodate the low ceilings of that time and were not always set symmetrically. Casements typically opened inward, infringing on interior space when fresh air was wanted. By the reign of William & Mary, building styles in England were moving to symmetrical facades externally, with higher ceilings and larger rooms internally. A new window design was needed for this new building style.

The sash window is an essentially English design. They were seldom to be found on the Continent beyond Holland, where they were probably first imported from England during the reign of William III. The name of these windows is a corruption of the French word, châssis, meaning frame, since they are, in fact, windows set in a frame. However, it should be noted that in France, by the end of the eighteenth century, where casement windows remained the norm, sash windows were most often known as windows à la guillotine because of the action by which they are opened and closed.

By the beginning of the Georgian era, the sash window had become the most common window form used in England, particularly for the principal windows of buildings. They were more vertical and taller than casement windows and were therefore more suited to rooms with taller ceilings and allowed in much more light to illuminate the larger rooms. Sash windows also tended to be more precise in size and shape than casement windows. This enabled them to be easily set into a building facade with the symmetry which had come into fashion with the advent of the Georgian architectural style. Because they were set into a closed frame, they significantly reduced drafts and, when open, they did not infringe on the interior space of a room.

The basic design of a sash window is a sash, or wooden frame, of small panes of glass set into wooden muntin bars. These small panes were typically cut from crown window glass and even today are commonly referred to as "lights." In the most common sash window layout, a sash was three lights wide by two lights high. In larger windows, a sash might be three rows of three lights. The most common sash window installation was two sashes, one over the other. In most cases, the upper sash was fixed, while the lower sash was set in a parallel frame which ran the full height of the window, inside the upper sash. The lower sash could then be raised and lowered along this inner track by means of a weight and pulley system. A cord or chain was attached to each side of the moveable sash, the cord was run up to the top of the track, where is was threaded through a pulley and attached to an iron weight set inside a second track enclosed in the window frame. In more expensive windows, both the upper and lower sash were set into tracks the full height of the window and weighted, so that either could be lowered or raised.

Until the early eighteenth century, all windows were set flush with the outer face of the building wall. In 1709, Parliament passed the Building Act, which required all doors and windows to be recessed at least an inch in from the outer face of the wall into which they were set. The intent of this law was to help slow the spread of fire by providing some protection to the wooden elements of a building. The walls of any structures built in London since the Great Fire of 1666 were required by law to be of brick or stone. Initially, many builders disregarded the requirements of the Building Act, but by the middle of the century the law was more regularly enforced, both in London and other cities and towns around the country. The earlier Window Tax also helped limit the number of windows in the facades of many middle and lower class homes, thus also reducing the amount of exposed wood.

The most well-designed and constructed sash windows had lower sills which were not flat. Rather, they slanted down at an angle toward the outside. The lower edge of the lower sash would be angled to match the angle of the sill. This was done to prevent water from rain or melting snow from standing in the sill or flowing toward the inside of the building. With the sill slanted downward toward the outside, the water would flow out of the sill away from the interior, even in a driving rain. This angle of sill and sash also helped to reduce drafts.

One secret of sash windows is that they could also be used as doors. A very large and elegant eighteenth-century summer house which I explored on an estate in Ireland had four such "doors" on the ground floor. The building was of stone, and in the center of each of the four facades was set a very tall sash window which actually extended the height of two stories, installed with the lower window sill flush with the floor of the rooms and the surrounding porch on the first story. Each of these windows was comprised of three sashes with three rows of three lights. The upper sash was fixed, but the other two were both mobile and on hot summer days, the occupants of the summer house could raise the two lower sashes by means of a lever set into the wall near the window, thus allowing a breeze to flow through the building and the occupants to enter or leave the summer house. There were no regular doors on the ground floor of this summer house. There was just one actual door, primarily used by the servants, which was in the basement level, and hidden from view by a grassy berm which surrounded the summer house.

Sash windows were also used as doors in a dining room in a large Georgian era house. Along the wall facing the terrace there were three windows, all comprised of two sashes, each of three rows of three lights. In this case, both of the sashes were mobile, but instead of being opened by raising them up, both sashes were lowered into a cavity which had been made for them in the basement. Once the windows were lowered, their exposed frames were hidden by a wooden cover which slipped into place once they were fully lowered into the basement pocket. The diners then had three "doors" by which they could leave or enter the dining room from the terrace, or just to enjoy a breeze on a fine evening.

Another secret of sash windows are their shutters. Many sash windows actually had two sets of shutters, one exterior and one interior, though few today would recognize the internal set because of their clever design. The outer shutters for most sash windows were louvered and were intended to be used primarily in summer. When closed, these external shutters would exclude most of the sunlight and its accompanying heat, while still admitting any air which might be blown in by a passing breeze. These louvered shutters also kept out birds and helped to reduce the number of insects coming in through open windows, since window screens had not yet been invented, as I noted in my recent article on cleaning paper-hangings.

Interior shutters were primarily used for excluding light, though they also served a secondary purpose as a security measure. Yet, unless you knew where to look, you might not even be aware that a sash window had interior shutters. Most interior shutters were of solid wood, double-hinged and folded back against the window frame so that they appeared part of the window embrasure. The panels of these shutters which were exposed when the shutters were folded away were carved to give the appearance of a deep section of molding on either side of the window. These shutters were typically made to fit so well into the space on either side of the window that unless you knew a shutter was there, it would not be obvious because they fit so snugly. Most also did not have exterior handles, rather there would be an indentation at the bottom or the side to be used to pull them free of the recess into which they were folded away. These shutters would then be opened out to cover the windows to block light and/or secure a room. These interior shutters usually had one or more hook and loop catches to secure them while they were closed over the window. Thus, even if someone on the outside was able to open a window, they would not be able to make an easy or quiet entrance into the room.

Sash windows which had interior shutters very often also had a window seat beneath the window, since the shutters created a deep space into which such a seat could easily be constructed. Many of these window seats were not solid, rather they were hollow, with the seat serving as the lid to the space, rather like a built-in storage chest. Some seats were hinged near the wall, others simply lifted off to give access to the space beneath. In most cases, the hinged seats were of finished, painted wood, on top of which might be placed a cushion for comfort when sitting. The lift-off lids were often upholstered, so there was no need for a separate cushion. The spaces inside these window seats were often quite large as the open space extended into the area under the recesses for the interior shutters on either side.

Though I have entitled this article Some Secrets of Sash Windows, none of these sash window features would have been a secret to those living during the Regency. They would have been well aware of them and would have taken them for granted. It is only those of us living today, in some cases even those living in old houses with sash windows, who are often unaware of the various aspects of sash window technology. By bringing these "secrets" of sash windows to the attention of Regency authors and their readers, I hope to provide options for future Regency novels. I think it would be a nice change of pace for a drawing room or dining room in a Regency novel to have sash windows which serve as an exit to the terrace, rather than the ubiquitous French doors with which we are all so familiar. Instead of peeking through draperies to spy on someone outside the house, especially on a bright summer day, this surreptitious surveillance could be conducted through the louvers of a set of closed exterior shutters. It might also be amusing, should an overly amorous hero, bent on seduction, climb up to the heroine’s bedchamber window, only to find the interior shutters closed and latched against him. And what valuable object or precious possession might be hidden away in the dark recesses of a window seat? As you have learned here, Regency windows were quite often more than just a hole in a wall filled in with panes of glass, as they usually are today.


About Kathryn Kane

Historian with a particular interest the English Regency era.   An avid reader of novels set in that time, holding strong opinions on the historical accuracy to be found in said novels.
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15 Responses to Some Secrets of Sash Windows

  1. Larissa Lyons says:

    Kathryn, I just stumbled upon your blog after doing a search on “parts of a window Regency England” for a current novella I’m writing. What fabulous posts! I’m delighted to have found such a phenomenal Regency resource. Thank you!

    • Kathryn Kane says:

      You are quite welcome. I am glad you happened by.

      Over the years, I have picked up so much esoteric information which I thought could be of use to novelists of the Regency era, that I thought I should record it. By publishing it here, I can make it available to any author might be looking for something fresh for a new story. I hope this information was helpful to you.



  2. That is one of the most complete articles on sash windows I have read in a good while. Do you write freelance? I would be interested in a few articles of this quality. Thanks Chris

    • Kathryn Kane says:

      Thank you very much for your kind words. Though I am flattered by your offer, my days of writing about specific topics on schedule are long past.

      These days, I research whatever point of Regency history takes my fancy, and write articles about those subjects which happen to pique my curiosity and which I hope will amuse and edify those who visit here.



  3. Dr Alan Shrank says:

    Your article is most interesting and useful.

    I am interested in the change from Georgian windows to Regency windows. Most domestic Georgian windows are three panes wide but most Regency windows are four panes wide. Is this your experience?

    I am also concerned about the design of glazing bars. Most Georgian windows have ‘lamb’s tongue’ glazing bars, which have a complex cross-section. When did this style disappear to be replaced by the more simple stronger glazing bars? Was it related to the change in the width of windows?

    Thirdly, there’s the glass quality. When did Crown glass fall out of favour? Cylinder glass came into fashion in 1834 in the UK, so what glass was used between these two dates, do you know? And when was cylinder glass replaced by flat glass? Was there a fashion change so important that householders changed their Georgian windows with Regency windows in terms of the style of glazing bars and style of glass, do you know?

    I await your answers with great interest. as we have a problem with restoration of windows in an 1825 house in a terrace in the UK.

    Kindest regards

    Alan Shrank

  4. Sarah Waldock says:

    I’d never come across using a sash window as a door and I must say, having narrowly avoided having a sash window crash on my head when the sash cord failed catestrophically I would be very chary about using one. There isn’t a big huge lead weight counterbalance inside them for nothing. It’s a lump of lead about 9″ long diameter 2″ for an ordinary 4′ x 2′ window so heaven knows the size of them for those two storey tall ones!
    I am thinking that perhaps sash windows may have benefited peripherally from the naval technology invented by Mark Brunel [father of the more famous Isambard Kingdom Brunel] who invented a machine to make blocks. The pulleys in our relatively modern house – 1897 – are cast in metal, but I’m guessing that the early ones were carved in wood like the blocks or pulleys onboard ships of the time?

    • Kathryn Kane says:

      Some window pulleys were made of wood, but even in the Regency, most pulleys were made of metal since they were faster to make than carving from wood. I doubt sash window pulleys were based on the much more complex block and tackle pulley type invented by Mark Brunel, as sash windows had been in use for at least a century before he was born.

      Many of the larger sash window weights were suspended by chains rather than cords, which were better able to take the strain of heavy window sashes without breaking.



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  7. Bernadette Ross says:

    Just for people who are interested in old windows! I worked for many years in a large house built around 1840. It had gothic windows. Some were casement, but several were sash windows which disappeared down into the wall, and some had just the bottom sash working. They were extremely heavy and you could hurt your back opening them but I suspect the glass, which was very thick, was not original. Several had the deep embrasures which you describe. We had the shutters freed from many layers of paint and restored. These were only on the downstairs windows, including the glazed parts of the front door. They had large and very sturdy iron fastenings. The shutters themselves were not flimsy, and when folded back were quite difficult to unfold across the windows-we fixed tape to pull them out! I thought they were great for security and for keeping the sun out in summer. My brother had a Georgian house in which the shutters (flimsy ones) seemed to roll sideways into the walls.
    I seem to remember a Victorian ‘real murder mystery’ in which one of the problems was that if the servants had closed the shutters, how would any intruder have got into the house. With the shutters in the building where I worked they would have had a problem.

    P.S. I am working my way through this whole site and thoroughly enjoying it. Thank You.

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  10. Jay Shadforth says:

    Do you have information regarding the manufacture of the sash window pulley? I have what I believe to be one with the markings “Secret Pulley” “British Made” “No 70” and “I 5/4”
    Any insights?

    • Kathryn Kane says:

      There is not much I can tell you. I have never seen an object like the one you describe, but that may be because I live in the States. However, the fact that it is marked suggests that it was machine made and therefore was probably made after the mid-nineteenth century, when mechanized manufacture became common. The term “secret” may be to indicate it was intended to be used inside the window case, meaning it was not visible once the installation was complete.

      Numbers on the pulley suggest that it was one of a series and was probably manufactured in high volume. Numbers also suggest that it was manufactured for use in buildings once standardized construction methods were introduced. Numbered parts were easy to call out in construction plans and other documents and assured the correct parts were used.

      It is possible that such a part might be listed in catalogs of building materials, though I cannot even hazard a guess at an approximate date. I doubt such documents have been put online, which means you would have to seek out repositories of old construction and hardware catalogs and then go through them manually. Even then, you might not learn more than who manufactured the part, maybe with an approximate date.

      Sorry I cannot provide any more information. God Luck in your search!



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