What Does a Window Mullion Mean in Architecture?
What Does a Window Mullion Mean in Architecture?
A mullion is a vertical element that forms a division between units of a window or screen, or is used decoratively.
Mullions are often used as a rigid support to the glazing of the window and to provide structural support to an arch or lintel above the window opening. 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.
Mullions appear with the invention of tracery and are particularly characteristic of Gothic architecture and early Renaissance architecture in northern and western Europe.
In traceried windows, mullions are chamfered or beveled on the edges and sometimes decorated in addition to a colonnette. In late Gothic work, more elaborate moldings are common.
A mullion refers to the vertical piece of wood separating panes of glass, not both the verticals and horizontal stile pieces. Today, mullions are the vertical bars between panes of glass in a window. As with muntins, their role is primarily for decoration nowadays as opposed to structural support.
Window Muntin Vs. Mullion
Muntins and mullions are architectural elements used in windows. Muntins are vertical and horizontal elements that divide a window’s glass into a grid.
They are found on the window glass itself and are usually placed as decorative elements. Mullions, on the other hand, are vertical shafts located in between windows.
They offer structural support for the windows and separate window units. Mullions can be installed in virtually any type of house, while muntins bring a traditional or classic look to a property.
Muntins were historically used because it was less expensive to use smaller pieces of glass rather than a large single pane of glass.
Nowadays, muntins are usually placed as decorative elements. Mullions have also been used as a decorative element in some architectural styles but primarily serve as a structural element.
Muntin bars, sash bars, or glazing bars refer to the framing that is used to separate and hold pieces of glass within a window. Typically, muntins are made of wood or metal.
When trying to keep the difference between muntin vs. mullion straight, it all comes down to what they divide. Muntins separate panes of glass, while mullions divide two or more windows or door frames together. They can run both horizontally or vertically.
How To Install A Window Mullion
To install a window mullion, place the windows to be mulled on a large table with the exterior side facing up. Remove the nail fins, if applicable, by bending them over where they meet the window.
The fins are plastic and should snap off neatly. Any unwanted protrusions can be trimmed away with a utility knife.
Install the snap mullion (or H mullion) to both the interior and exterior sides of both windows. From inside the home, install screws through the pre-drilled holes in each corner of the mull plate into the framing members of each window.
Attach the mull plates to the top and bottom of the window frame. The plates should lay across the seam where the windows have been joined. Different types of windows may require different installation methods.
Window Mullion Design Ideas
Window mullion design ideas can be found in a variety of places, including home design websites such as Houzz, Avanti Systems, and Etsy.
Mullions are vertical dividers that break apart the opening of a window, and they have been used since the 10th century for both structural and decorative purposes.
They are commonly made from materials such as timber, aluminium, steel, and UPVC. Window mullion designs can range from classic to modern, depending on the desired aesthetic.
For example, exposed wires can give an industrial feel to a space, while vintage white wood diamond frames can add a cottage-style look to a kitchen.
How To Replace A Window Mullion
To replace a window mullion, the damaged muntin must first be removed from the glass. This can be done by cutting along both sides of the muntin with a utility knife and then prying it up with a screwdriver.
The profile of an intact muntin should then be captured using a profile gauge and traced onto a plastic scraper.
The scraper should then be cut out using a coping saw and fine-tuned with a triangular slim-taper file. Epoxy should then be applied to the damage and shaped using an intact scraper.
Finally, the replacement muntin should be tapped into place over the glass using a hammer and screwdriver.
It is important to note that muntins are different from mullions. Muntins are thin, profiled pieces of wood that fit together to hold the window in place in a grid, while mullions are vertical bars between glass panes in a window.
Window Mullion Replacement Cost
Replacing the mullions in a window or door will cost between $200 and $500. A full window replacement, on the other hand, will cost anywhere from $2,000 to $3,800. The average cost of window glass replacement is between $280 and $325 per window.
Minor glass repairs can cost as little as $70 while total window glass replacements can cost as much as $800. Window glass replacement costs range from $180 to $410.
The thickness of the pane affects the overall cost of a window replacement. Double-paned glasses come with many benefits but they will cost more to replace than a single-paned window – especially if the window is filled with argon or krypton gas.