A roof valley is located where two sloped roofs meet, it’s designed to guide rainwater down the roof where it then typically discharges into the guttering.
Roof valleys are subjected to more rainwater than any other part of the roof. During a downpour, the valley can experience a torrent of water, and it’s not uncommon for older valleys to leak.
A common issue is leaks caused by blockages.
If the valley is full of leaves, twigs and other organic materials such as pine needles or roof moss, rainwater may back up and enter the loft via the overlapping tiles.
Blockages are fairly easy for a roofer to resolve and the work shouldn’t take long.
If however, the leak is due to failure of the valley components, then a complete replacement or substantial repair may be required.