Glass Glossary

Simulated Divided Lites (SDL)

Last Updated: November 23, 2023

Simulated Divided Lites (SDL) are a type of window design that replicates the appearance of traditional multi-pane windows using a single pane of glass with applied external bars. The decorative bars are typically made of wood, vinyl, or aluminum, and are adhered to the interior and exterior surfaces of the window glass, creating the illusion of separate panes of glass. Additionally, a spacer bar is often placed between the layers of glass in an insulating glass unit to enhance the authenticity of the divided lite appearance.

Compared to traditional divided lites, where each section is a separate piece of glass held together by a grid of muntins, SDLs offer several advantages. SDL windows are more energy-efficient, as they eliminate the thermal bridges created by muntins in traditional divided lites.