Mullion - Wikipedia A mullion is the vertical element that forms a division between units of a window or screen, or is used decoratively [1] When dividing adjacent window units its primary purpose is a rigid support to the glazing of the window
A Manual to Designing with Mullioned Windows - The Painted Hinge Mullioned windows use strong vertical bars, called mullions, made of stone or wood to divide large openings into smaller sections In medieval times, this was practical since big glass sheets were rare and costly Millions ran from top to bottom, strengthening the frame
What is a Mullion in Construction? At its core, a mullion is a vertical or horizontal element that divides and separates windows or doors Its primary purpose is to provide additional support to the structure while also contributing to the overall design aesthetics
Window Mullions vs. Window Muntins: Differences - The Spruce Generally, mullions are the single vertical bars that separate two sides of a single window Another way to think of them is that mullions are often heavier elements that divide larger window frames Sometimes they can appear to create two windows where one window would be expected
Mullions vs Muntins Window: Key Differences Guide [2026] The purpose of a mullion is to separate and support multiple window units Mullions strengthen large window openings and help distribute the weight of the glass and frame
Window Mullions Explained: What They Are When to Use Them Mullions separate window frames Muntins separate window glass That’s the key distinction most people miss A mullion creates multiple window units Picture a large opening with three casement windows side by side—the vertical bars between each window are mullions They’re part of the window frame system and provide structural support
What is a Mullion? - Security Door Function - Vortex Doors A mullion is a vertical bar that divides a door or window frame into separate sections Invented during the Middle Ages, they were a common design element in Renaissance, Victorian, and Gothic architecture
What Is A Door Window Mullion? - panda-windows. com A mullion is a vertical or horizontal partition that divides units within a window or door frame Its prime purpose is to give structural support and add more visual appeal to the installation