What is a mullion in construction?

A mullion is defined as a vertical member that separates the panels of a window, door, or other openings. It plays a crucial role in the structural integrity and aesthetics of these openings by providing support and creating distinct divisions within large expanses of glazing or paneling. Mullions can also enhance the overall design by adding visual interest and allowing for a variety of configurations in the layout of the openings.

This distinction is critical in architectural design, as mullions help to manage the weight of the materials they support and help in weather resistance by facilitating water drainage. Understanding the function of mullions is essential for professionals in construction and architecture as they contribute significantly to both form and function in building design.