Sash Styles | Types Of Sash Window
The counterbalanced vertically sliding wooden sash window started to take shape in 1670’s London, at about the same time as rapid improvements in glass quality were happening. By the turn of that century the double-hung sliding sash was introduced, although it was not widely adopted until the mid eighteenth century. From that period onward the double hung sash remained popular, being adapted to suit varying architectural styles.
Universal Designs For Pairs Of Sashes
Most sash window designs have no formal name so the manufacturers generally only numbered each design, although localised ‘nick-names’ were not uncommon. The design variations are endless …
Describing sliding sash windows
Wooden sash windows are usually described by the number of glazing panes per sash. 6 over 1 would have 6 smaller panes of glass in the top sash and 1 larger pane in the bottom alternatively this could be described as a 7 light window.
Basic Glazing Configurations
Georgian Sash Windows
The Georgian era includes the rein of George I, George II, George III, and George IV—who reigned in continuous succession from August 1714 to June 1830. Windows in the Georgian era were almost exclusively sash-windows, consisting of multiple smaller panes of glass divided by wooden glazing bars (muntins). Early Georgian windows had thick oak glazing bars, upto 38mm thick, but later thin delicate bars carved from ‘Deal’ (Baltic Pines) were as thin as 12mm. The narrow glazing bars allowed for larger window sashes with a less interrupted view.
- Sash horns are not normal for Georgian era windows, both the top and bottom sashes should be squared off. Horns were not required because the lattice of glazing bars disperses the glass weight to be carried by the sash rails.
- On Georgian box sash windows the sash pocket is usually set in the middle of the pulley stile with a central groove for the parting bead, alternatively it may be located internally hidden behind wooden shutters.
In Georgian Britain, glass production was still limited to small panes of handmade crown glass, made by spinning hot glass on a punty rod. Crown glass was very expensive due to heavy government taxation, that was calculated by weight, encouraging very thin glazing to be used.
Victorian Sash Windows
The group of styles collectively referred to as Victorian architecture is a series of architectural revival styles adopted during the rein of Queen Victoria, from 1837 to 1901.
Victorian Gothic revival sash windows incorporated curved horns, arched heads, intricate mouldings, lead-lights and latticework to adorned the sashes. Windows were often grouped into impressive bays, offset with ornate stone reveals.
Queen Anne revival homes were embellished with bay windows and oriels. Bottom window sashes had only a single pane of glass with the upper sash being multi-paned in a six over one configuration. More elaborate windows featured sashes with stained glass in the upper portion.
Late Victorian windows were simpler, typically with either single panes or two over two vertical split glazing pattern. Square or canted bay sash windows with stone sills became a common feature.
As well as building housing stock the Victorians also constructed many of the civic heritage buildings that remain today; Schools, libraries, museums, churches, shopping arcades and town halls often feature the finest examples of Victorian craftsmanship and design in their sash windows.
- Larger panes of glass removed the necessity for many glazing bars but the meeting rail of the top sash needed to be reinforced, with the addition of sash horns, to carry the additional glass weight.
- The sash pocket was no longer located in the middle of the pulley style, instead it was hidden behind the lower sash and held in place by the parting bead sitting in a rebate along one edge of the pocket.
Victorian Window Glass
Larger and thicker sheets of window glass were developed by the Victorians using the cylinder method. A large cylinder of glass was mouth blown, split open and then flattened out. Once the heavy taxation of glass was repealed, in the middle of the century, cylinder glass soon displaced crown glass production.
As well as revolutionising the ‘white’ or clear window glass industry the Victorians also introduced many types of decorative glass processes.
Shaped Top Sash
Bent / Bow Faced Timber Sash Windows.
A true bow faced window is constructed with segmental sashes, that are bow-shaped on plan, fitted with glass that has been bent by heating a flat sheet until it slumps’ into a curved mould. A cheaper version uses the same bowed segmental sashes but the rebates are set to accept flat glass sheets.
A similar effect was also created using flat sashes and flat glass with the frame bowed.
Marginal Glazing Bars
Margin light windows have a larger central pane flanked by narrow glass panes that enhance the variety and elegance of fenestration. The marginal panes were generally set at 4 inches and often incorporated coloured enamelled glass as a feature. First introduces circa 1828 marginal patterns remained popular, in various forms, until the end of the 19th century.
Tripartite windows comprise a large central light flanked by two smaller lights, a form that can be traced back to Roman architecture. As this style became especially popular in Venice during the mid sixteenth century they are now commonly known as Venetian windows. Wooden Venetian windows may feature stone, brick or timber-framed construction.
Venetian Window Variations
Eighteenth Century Palladian windows are stepped tripartite windows with a taller arched central light. Also known as Gable windows, Serliana or Serlian Motif.
Medieval triptych windows have three pointed lights joined up in series. The lights may be of equal size or the centre light may be taller, similar to the Palladian window.
Venetian Wooden Sash Window – with narrow mullions.
The sash cords in this style of Venetian window pass above the sidelights to reach the weight boxes on either side of the frame. The side sashes are fixed in place and must be removed in order to replace the sash cords.
Venetian windows with wide timber mullions (triple box sash) or masonry framing are treated as three individual windows.
A bay or bow window protrudes beyond the straight brick-line of a building, increasing the natural light, views and the living space of a room. Bay windows evolved from the flat tripartite Venetian style and may comprise a group of casement or sliding sash windows. A house with a timber bay or oriel window was most likely built after 1894 when an amendment to the building act decreed that windows no longer need be flush with the exterior wall. The word bay is believed to derive from the French word ‘baee’, which means opening or hole.
Canted bay windows (splayed bay) are those with a straight front and angled sides that became a particularly popular feature of middle-class Victorian terraced houses.
Square bay windows are rectangular with 90 degrees (square) corners. Commonly seen on Edwardian period property.
Bow Windows are semi-circular or elliptical in plan.
An oriel window is a style of bay window that does not reach to the ground. Instead oriel windows are usually supported by corbels or brackets.
Canted/Splayed Bay Sash Window | Masonry Fame Construction
Canted / Splayed Bay Sash Window | Timber Frame Construction
Other Types – Timber Sash Windows.
External Links – Wikipedia