This, unfortunately, is all too common: Your roof seems to be perfectly okay when it’s dry outside, but after rainfall, you start seeing either a damp patch or water dripping in your loft!! This is because heavy rain not only tests the roof, but it also reveals weak points that have been struggling quietly for months (or years).
One cause is wind-driven rain. The rain is being forced sideways and even upwards, making its way under tiles and into gaps that would be non-issues in fair weather. Heavy rain will take the path of least resistance if you have slightly slipped tiles, cracked ridge mortar, or worn flashing around chimneys and valleys. For Roofers Selsey, visit www.randsroofing.co.uk/roofing-services/roofers-selsey/
The second major problem with water is blocked gutters and downpipes. If water cannot move, that means it will flood over the top of what is there. This overflow can flow behind fascia boards, penetrate brickwork, and manifest itself inside a property as a ‘roof leak’.
A flat roof can also be flooded after heavy rain. If it takes hours for permanent ponds to form, your roof may only leak in that situation. Are you seeing small dips (ponding), felt rippling, or sealed joints/seams splitting in EPDM/GRP?
In the same way, valleys (the point where two roof slopes meet) can get choked up if they are full of moss, leaves, or silt.
In fact, the leak may not even be new – it might just have emerged from obscurity. Small drips can remain hidden for some time, as loft insulation soaks them up, but the arrival of a heavy downpour will drive their volume to levels high enough that at last they reach the ceiling.
If you are seeing leaks after heavy rains, do not ignore them. A roofer is able to follow the path of entry, inspect your flashing and drainage area, and repair that one weak spot before another storm adds more damage.