One of the points in your roof structure that may fail is the flashing. The flashing is the material that is used to cover over joints between different roofing materials such as between the tiles and a chimney or tiles and a wall on perhaps a single story extension.
Lead flashing protects your roof from leaks where parts meet and there is a break in the tiled surface
The flashing used may vary from home to home, but the traditional material commonly found in homes in the UK is lead. Other materials used include copper, aluminium and even galvanised steel.
If your roof is leaking, one of the first places to look is the flashing. The flashing should always be in a good state of repair and fixed firmly to the area it is protecting. If the flashing is cut into a wall or a chimney and fixed into place using mortar, the mortar should be checked for soundness and any signs of damp on the roof investigated.
When the flashing is inspected it is usually easy to see problem straight away. However, in some instances the flashing may need to be removed completely and replaced with new before the root cause of the problem is solved.