spröjs

Spröjs is a term used in Swedish and some other Northern European architectural contexts to describe the bars that divide and support panes of glass within a window. The spröjs may be fixed to the sash or positioned between panes of glass in a true divided-light window. The purpose is both structural and aesthetic, providing a traditional grid pattern and, in some cases, helping to hold multiple panes of glass in a single frame.

Traditionally spröjs were made of wood, but metal and later vinyl or composite materials have also been used. In historic windows, each pane is a separate piece of glass held in place by the muntins (spröjs), with the outer frame (mullion) providing structure. In modern construction, the "grid" appearance can be achieved with true muntins in dual-glazed units or with external or internal grilles placed on or between insulated panes (grilles-between-the-glass, GBG) to mimic the historical look while improving energy efficiency.

Common patterns include vertical and horizontal muntins forming a rectangular grid, or more intricate geometric patterns in smaller panes. The design depends on regional styles and historical periods, ranging from simple two- or four-pane arrangements to complex tracery in ecclesiastical architecture.

In preservation and restoration, spröjs are important for maintaining historical accuracy. See also muntin, mullion, glazing, and window grille.