A window armature is the framework of horizontal and vertical bars, mullions and arches in a window — usually of stone or iron, sometimes of wood. It divides the window into panels and gives large glass areas, such as stained-glass windows, the strength they need.
Function
The armature has two roles:
- Structural — it carries and stiffens the glass. Large stained-glass windows would sag and fail under wind and their own weight without it
- Aesthetic — the arrangement of bars and arches helps determine the appearance of the window and suits the architectural style
The Dutch term for it (harnas) derives from medieval French words for armour — a reference to the load-bearing, protective nature of the framework.
Application
- Churches and monumental buildings — large painted windows rest in a stone framework with tracery
- Historic windows — iron armatures (with saddle bars) hold lead panels in place
- Restoration — when repairing old windows, the armature is checked for rust, cracks and sagging
Points to watch
Iron parts can rust and expand, which can crack the stone. During restoration, rusting iron is treated or replaced with rust-resistant material.
Related terms
- Stained glass
- Window
- Mullion
- Tracery
- Natural stone
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