Flashing is a crucial element in making a building weather-resistant and preventing water from entering the building by diverting it away. Installed on roofs around chimneys, skylights and roof edges, flashing is usually made of aluminium or galvanised material. Poorly installed flashing or flashing that has rusted or come loose is a common cause of a roof leak. Skylight leaks are a pervasive problem, and poor flashing is usually the cause. In older buildings, chimney leaks are common. If...