The glazing industry has always responded to architect’s desire for enhanced glazing details, providing options that meet the design intent and address budget constraints. Such is the case of divided lite window glazing, the subject of this Technical Bulletin.
Divided lite windows are characterized by their distinct grid of smaller panes of glass, separated by vertical and horizontal muntin bars. Historically, these windows were constructed to allow for the use of smaller glass panes, which were easier to produce and transport compared to large, single sheets of glass. Today, they are still widely used in both traditional and modern construction for their unique aesthetic and classic design.
With a variety of material options, there are different ways to achieve detailing of divided lite windows, each with their own aesthetic effect, practical benefits and cost.
True Divided Lite Windows
True divided lite windows are where each individual glass pane is separated by muntin bars. This type of window is typically found in older buildings and historical restorations. True divided lite windows are considered highly authentic and maintain the original look and feel of buildings from past centuries.
True divided lite windows offer a genuine classic appearance than others but are more expensive due to higher material and labor costs. Maintenance is typically greater than other options because of the individual weather seals, cleaning or replacement.
Simulated Divided Lite Windows
Simulated divided lite windows have the appearance of true divided lite windows, but they feature a single pane of glass with muntin bars applied to the exterior and sometimes interior surfaces. These bars are often adhered to the glass using adhesive or can be integrated with the frame. For insulated glazing, internal dividers can be provided to visually block the back view of the adhered muntins.
Simulated divided lite windows are more cost effective than true divided lite windows, easier to clean, and offer a similar aesthetic. Simulated divided lite windows can also have better insulating properties, as it provides one light of glass and no heat or cold transmission at the muntins.
Grilles Between Insulated Glass
Grilles between the glass lites of an insulated glass unit are a variation of simulated divided lite windows. In these windows, internal grid bars provide a divided lite effect, but not of the same visual impact as the external/internal muntin options. Further, coated glass may diminish the aesthetic impact of these grilles.
Internal grilles within the insulated glass offer the most economical solution and provide ease of maintenance in cleaning. Much like the simulated divided lites, they have better insulating properties, providing one lite of glass and no heat or cold transmission at the muntins.
With their ability to enhance the visual appeal in a project design, divided lite windows will remain a staple in both modern and traditional construction. Understanding and addressing aesthetic considerations, maintenance issues and costs is essential for informed decisions.
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