You should regularly check your church windows for damage. Look for the following signs:
- water droplets on the glass
- a greenish layer of algae growing on the glass
- pitting and discolouration of the glass surface
- loss of colour and flaking off from painted areas of glass
- loose or rattling glass
- any bowing or bulging of the glass
- rusting of the window's iron framework (known as the ferramenta)
- cracks or white, powdery deposits on the lead dividers (known as the leading)
- water staining to the stone, mortar or brickwork around the window
- moss, algae or mould growing around the window inside or outside
- damaged and crumbling stone, mortar or brickwork around the window