Issues · 8 min read
Sudden roof leaks after heavy Cobham rain — moss, gutters or something worse?
A leak that only shows after heavy rain rarely means a roof at end of life. Here is how to work out whether it is gutters, moss, valleys or flashing.
Rule out the gutters first
70% of the 'sudden leaks' we investigate in Cobham are actually gutter overflow soaking the wall head, then travelling internally along a joist and dripping several metres from the real source. A £95 gutter clear often ends the leak entirely.
Then check moss-blocked valleys
Where two roof pitches meet, a lead or GRP valley channels huge volumes of water. A dense moss dam upstream diverts water sideways under the tiles — invisible from the ground but obvious from a drone survey.
Flashing and lead work
Chimney flashing on 1930s Cobham semis is often the original lead — 90+ years old and pinholed. Heavy rain finds every pinhole. A dressed lead patch is a same-day repair.
When it really is the tiles
Slipped or frost-cracked tiles typically leak in a steady drip during any rainfall, not just heavy events. If your leak scales with rainfall intensity, it is almost never a tile issue.
Get your free roof cleaning quote
Fixed-price quote within 24 hours. No call-back chasing — we'll email you.