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