A mullion is a vertical element that forms a division between units of a window or screen, or is used decoratively. [1] It is also often used as a division between double doors. When dividing adjacent window units its primary purpose is a rigid support to the glazing of the window. Its secondary purpose is to provide structural support to an arch or lintel above the window opening. Horizontal elements separating the head of a door from a window above are called transoms.
Stone mullions were used in Armenian, Saxon and Islamic architecture prior to the 10th century. They became a common and fashionable architectural feature across Europe in Romanesque architecture, with paired windows divided by a mullion, set beneath a single arch. The same structural form was used for open arcades as well as windows, and is found in galleries and cloisters.
In Gothic architecture, windows became larger and arrangements of multiple mullions and openings were used, both for structure and ornament. This is particularly the case in Gothic cathedrals and churches where stained glass was set in lead and ferramenta between the stone mullions. Mullioned windows of a simpler form continued to be used into the Renaissance and various Revival styles. Italian windows with a single mullion, dividing the window into two equal elements are said to be biforate, or to parallel the Italian bifore windows. [2]
Mullions may be made of any material, but wood and aluminium are most common, although glass is also used between windows. [3] I. M. Pei used all-glass mullions in his design of JFK Airport's Terminal 6 (National Airlines Sundrome), unprecedented at the time. [4]
Mullions are vertical elements and are often confused with transoms, which lie horizontally. In US parlance, the word is also confused with the "muntin" ("glazing bar" in the UK) which is the precise word for the very small strips of wood or metal that divide a sash into smaller glass "panes" or "lights".
A mullion acts as a structural member, in most applications the mullion transfers wind loads and weight of the glazing and upper levels into the structure below. In a curtain wall screen, however, the mullions only support the weight of the transoms, glass and any opening vents. Also in the case of a curtain wall screen the weight of glazing can be supported from above (providing the structure can take the required loads) this puts the mullions under tension rather than compression.
When a very large glazed area was desired before the middle of the nineteenth century, such as in the large windows seen in Gothic churches or Elizabethan palaces, the openings necessarily required division into a framework of mullions and transoms, often of stone. It was further necessary for each glazed panel, sash or casement to be further subdivided by muntins or lead cames because large panes of glass were reserved primarily for use as mirrors, being far too costly to use for glazing windows or doors.
In traditional designs today, mullions and transoms are normally used in combination with divided-light windows and doors when glazing porches or other large areas.
A window is an opening in a wall, door, roof, or vehicle that allows the exchange of light and may also allow the passage of sound and sometimes air. Modern windows are usually glazed or covered in some other transparent or translucent material, a sash set in a frame in the opening; the sash and frame are also referred to as a window. Many glazed windows may be opened, to allow ventilation, or closed to exclude inclement weather. Windows may have a latch or similar mechanism to lock the window shut or to hold it open by various amounts.
A shoji is a door, window or room divider used in traditional Japanese architecture, consisting of translucent sheets on a lattice frame. Where light transmission is not needed, the similar but opaque fusuma is used. Shoji usually slide, but may occasionally be hung or hinged, especially in more rustic styles.
A curtain wall is an exterior covering of a building in which the outer walls are non-structural, instead serving to protect the interior of the building from the elements. Because the curtain wall façade carries no structural load beyond its own dead load weight, it can be made of lightweight materials. The wall transfers lateral wind loads upon it to the main building structure through connections at floors or columns of the building.
Tracery is an architectural device by which windows are divided into sections of various proportions by stone bars or ribs of moulding. Most commonly, it refers to the stonework elements that support the glass in a window. The purpose of the device is practical as well as decorative, because the increasingly large windows of Gothic buildings needed maximum support against the wind. The term probably derives from the tracing floors on which the complex patterns of windows were laid out in late Gothic architecture. Tracery can be found on the exterior of buildings as well as the interior.
Rayonnant was a very refined style of Gothic Architecture which appeared in France in the 13th century. It was the defining style of the High Gothic period, and is often described as the high point of French Gothic architecture. French architects turned their attention from building cathedral of greater size and height towards bringing greater light into the cathedral interiors and adding more extensive decoration. The architects made the vertical columns and supports thinner, made extensive use of pinnacles and moldings. They combined the triforium gallery and the clerestory into single space and filled it with stained glass. They made extensive use of moldings and bar tracery to decorate the exteriors and interiors.
This page is a glossary of architecture.
Storm windows are windows that are mounted outside or inside of the main glass windows of a house. Storm windows exist in North America, but are uncommon in continental Europe, where double, triple or quadruple glazing is prevalent. Storm windows can be made of glass, rigid plastic panels, or flexible plastic sheets; and may be permanently or temporarily mounted. They function similarly to insulated glazing. The term may also refer to a small openable flap found in the side window on light aircraft.
A sash window or hung sash window is made of one or more movable panels, or "sashes". The individual sashes are traditionally paned windows, but can now contain an individual sheet of glass.
Leadlights, leaded lights or leaded windows are decorative windows made of small sections of glass supported in lead cames. The technique of creating windows using glass and lead came to be known as came glasswork. The term 'leadlight' could be used to describe any window in which the glass is supported by lead, but traditionally, a distinction is made between stained glass windows and leadlights; the former is associated with the ornate coloured-glass windows of churches and similar buildings, while the latter is associated with the windows of vernacular architecture and defined by its simplicity.
A muntin (US), muntin bar, glazing bar (UK), or sash bar is a strip of wood or metal separating and holding panes of glass in a window. Muntins can be found in doors, windows, and furniture, typically in Western styles of architecture. Muntins divide a single window sash or casement into a grid system of small panes of glass, called "lights" or "lites".
Albany City Hall is the seat of government of the city of Albany, New York, United States. It houses the office of the mayor, the Common Council chamber, the city and traffic courts, as well as other city services. The present building was designed by Henry Hobson Richardson in the Romanesque style and opened in 1883 at 24 Eagle Street, between Corning Place and Pine Street. It is a rectangular three-and-a-half-story building with a 202-foot-tall (62 m) tower at its southwest corner. The tower contains one of the few municipal carillons in the country, dedicated in 1927, with 49 bells.
In architecture, a transom is a transverse horizontal structural beam or bar, or a crosspiece separating a door from a window above it. This contrasts with a mullion, a vertical structural member. Transom or transom window is also the customary U.S. word used for a transom light, the window over this crosspiece. In Britain, the transom light is usually referred to as a fanlight, often with a semi-circular shape, especially when the window is segmented like the slats of a folding hand fan. A prominent example of this is at the main entrance of 10 Downing Street, the official residence of the British prime minister.
Glass mullion system or glass fin system is a glazing system in which sheets of tempered glass are suspended from special clamps, stabilized by perpendicular stiffeners of tempered glass, and joined by a structural silicone sealant or by metal patch plates.
Glazing, which derives from the Middle English for 'glass', is a part of a wall or window, made of glass. Glazing also describes the work done by a professional "glazier". Glazing is also less commonly used to describe the insertion of ophthalmic lenses into an eyeglass frame.
Insulating glass (IG) consists of two or more glass window panes separated by a space to reduce heat transfer across a part of the building envelope. A window with insulating glass is commonly known as double glazing or a double-paned window, triple glazing or a triple-paned window, or quadruple glazing or a quadruple-paned window, depending upon how many panes of glass are used in its construction.
A skylight is a light-permitting structure or window, usually made of transparent or translucent glass, that forms all or part of the roof space of a building for daylighting and ventilation purposes.
Our Lady of Assumption Convent is a heritage-listed former Roman Catholic convent at 8 Locke Street, Warwick, Southern Downs Region, Queensland, Australia. It was designed by Simkin & Ibler and built from 1891 to 1914. It is also known as Assumption College, Cloisters, and Sophia College. It was added to the Queensland Heritage Register on 21 October 1992.
Temora Post Office is a heritage-listed post office at 173 Hoskins Street, Temora, New South Wales, Australia. It was added to the Australian Commonwealth Heritage List on 8 November 2011.
A Chicago window is a large fixed glass panel flanked by two narrower sashes of the same height, filling a structural bay. The large pane is a single panel of plate glass, and the flanking elements are vertical double-hung sash windows with no dividing muntins. The fenestration was first used by architect William LeBaron Jenney in the 1884 Home Insurance Building, and immediately after by several of the Chicago School architecture firms such as Holabird and Root in their Marquette Building (Chicago), Daniel Burnham's Fisher Building (Chicago), and Louis Sullivan's Carson Pirie Scott department store. The window design was made possible by advances in glass-making technology and steel structural framing, and became a defining feature of the Chicago school style. The design offered both abundant natural light and practical ventilation. Projecting oriel bays are a common variant of the Chicago window, as seen here in the Reliance Building(1895) by Burnham and Root.
In architecture, a paned window is a window that is divided into panes of glass, usually rectangular pieces of glass that are joined to create the glazed element of the window. Window panes are often separated from other panes by lead strips, or glazing bars, moulded wooden strips known as muntins in the US.
Media related to Mullions at Wikimedia Commons