Muntin
Encyclopedia
Muntin or Muntin bar is a strip of wood or metal separating and holding panes of glass
in a window. Muntins are also called "glazing bars", "muntin bars", or "sash bars". Muntins can be found in door
s, window
s 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".
Windows with "true divided lights" make use of thin muntins, typically 1/2" to 7/8" wide in residential windows, positioned between individual panes of glass. In wooden windows, a fillet
is cut into the outer edge of the muntin to "stop" the pane of glass in the opening, and putty or thin strips of wood or metal are then used to hold the glass in place. The inner sides of wooden muntins are typically milled to traditional profiles. In the U.S., the thickness of window muntins has varied historically, ranging from very slim muntins in 19th century Greek revival buildings to thick muntins in 17th and early 18th century buildings.
Until the middle of the 19th century, it was economically necessary to use smaller panes of glass
, which were much more affordable to produce, and fabricate into a grid to make large windows and doors. However, many considered the division of a window or glazed door into smaller panes to be more architecturally attractive than use of large panes. In the UK and other countries, muntins (typically called "glazing bars" in the UK, or "astragals" in Scotland) were nevertheless removed from the windows of thousands of older buildings during the nineteenth century in favor of large panes of plate glass. Restoration of these buildings in the following century increasingly included reinstatement of the glazing bars, which many now see as an essential architectural element in period buildings.
Muntins are often confused with "mullion
s" (which separate complete window units), and "astragal
s" (which close the gap between two leaves of a double door). Many companies use the term "grille" when referring to a decorative structure of wood or other material that is put over a single pane of glass to make it look as if there were muntins separating multiple panes of glass. In the UK, the term "grille" tends to be used only when there are bars sandwiched within the insulated glass glazing unit, and not stuck to the outsides of it.
Double or triple layer insulated glass can be used in place of ordinary single panes in a window divided by muntins, though this reduces the effectiveness of the insulation. Other insulating glass arrangements include insertion of a decorative grid of simulated metal, wooden or plastic muntins sandwiched between two large panels of glass, sometimes adding an additional grid of simulated wood muntins facing the interior to produce a more convincing divided light appearance.
Glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
in a window. Muntins are also called "glazing bars", "muntin bars", or "sash bars". Muntins can be found in door
Door
A door is a movable structure used to open and close off an entrance, typically consisting of a panel that swings on hinges or that slides or rotates inside of a space....
s, window
Window
A window is a transparent or translucent opening in a wall or door that allows the passage of light and, if not closed or sealed, air and sound. Windows are usually glazed or covered in some other transparent or translucent material like float glass. Windows are held in place by frames, which...
s and furniture, typically in western styles of architecture. Muntins divide a single window sash or casement
Casement window
A casement window is a window that is attached to its frame by one or more hinges. Casement windows are hinged at the side. A casement window (or casement) is a window that is attached to its frame by one or more hinges. Casement windows are hinged at the side. A casement window (or casement) is a...
into a grid system of small panes of glass, called "lights" or "lites".
Windows with "true divided lights" make use of thin muntins, typically 1/2" to 7/8" wide in residential windows, positioned between individual panes of glass. In wooden windows, a fillet
Fillet
Fillet may refer to:*Fillet , a headband*Fillet , a piece of meat*Fillet , the filling of an interior corner*Annulet , part of a column capital...
is cut into the outer edge of the muntin to "stop" the pane of glass in the opening, and putty or thin strips of wood or metal are then used to hold the glass in place. The inner sides of wooden muntins are typically milled to traditional profiles. In the U.S., the thickness of window muntins has varied historically, ranging from very slim muntins in 19th century Greek revival buildings to thick muntins in 17th and early 18th century buildings.
Until the middle of the 19th century, it was economically necessary to use smaller panes of glass
Float glass
Float glass is a sheet of glass made by floating molten glass on a bed of molten metal, typically tin, although lead and various low melting point alloys were used in the past. This method gives the sheet uniform thickness and very flat surfaces. Modern windows are made from float glass...
, which were much more affordable to produce, and fabricate into a grid to make large windows and doors. However, many considered the division of a window or glazed door into smaller panes to be more architecturally attractive than use of large panes. In the UK and other countries, muntins (typically called "glazing bars" in the UK, or "astragals" in Scotland) were nevertheless removed from the windows of thousands of older buildings during the nineteenth century in favor of large panes of plate glass. Restoration of these buildings in the following century increasingly included reinstatement of the glazing bars, which many now see as an essential architectural element in period buildings.
Muntins are often confused with "mullion
Mullion
A mullion is a vertical structural element which divides adjacent window units. The primary purpose of the mullion is as a structural support to an arch or lintel above the window opening. Its secondary purpose may be as a rigid support to the glazing of the window...
s" (which separate complete window units), and "astragal
Astragal
An astragal is a moulding profile composed of a half-round surface surrounded by two flat planes . An astragal is sometimes referred to as a miniature torus...
s" (which close the gap between two leaves of a double door). Many companies use the term "grille" when referring to a decorative structure of wood or other material that is put over a single pane of glass to make it look as if there were muntins separating multiple panes of glass. In the UK, the term "grille" tends to be used only when there are bars sandwiched within the insulated glass glazing unit, and not stuck to the outsides of it.
Double or triple layer insulated glass can be used in place of ordinary single panes in a window divided by muntins, though this reduces the effectiveness of the insulation. Other insulating glass arrangements include insertion of a decorative grid of simulated metal, wooden or plastic muntins sandwiched between two large panels of glass, sometimes adding an additional grid of simulated wood muntins facing the interior to produce a more convincing divided light appearance.