A leak is the most common reason homeowners call a roofer, and it is also one of the most misdiagnosed problems. The damp patch on your ceiling is often some distance from where the water is actually getting in, because water travels along timbers and underlay before it drips. This article covers the most common causes of roof leaks and why a proper inspection matters.
Cracked, slipped or missing tiles
The most obvious cause. A slipped or broken tile lets water straight through the covering. Wind, frost and age all contribute. Isolated damage is a straightforward roof repair.
Failed lead flashing
Lead flashing seals the junctions between the roof and chimneys, walls and valleys. When it cracks, perishes or splits — often from thermal movement or the wrong lead thickness — water gets in at these vulnerable points. See our leadwork page.
Chimney defects
Chimneys are fully exposed above the roofline. Weathered mortar joints, cracked flaunching around the pots and failed flashing all let water in — often some way from the visible damp. Read our chimney repairs page.
Blocked or damaged valleys
Valleys carry a large volume of water where two slopes meet. A cracked lining, slipped tiles beside the valley, or debris choking the channel causes water to overtop and leak. See our roof valleys page.
Flat roof splits and ponding
Flat roofs leak through splits, blisters, failed seams and ponding water. Felt and GRP systems age and fail over time. See our flat roofing page.
Poor flashing at abutments and penetrations
Where the roof meets a wall, or around pipes and roof windows, poorly detailed or aged flashing is a common leak source. We check every abutment and penetration during an inspection.
Tracing the real source
Because water travels, patching the obvious damp rarely fixes the leak. We inspect the roof — using drone imagery where needed — to find the true entry point before recommending a repair. Arrange an inspection through our quote form.
Frequently asked questions
Why is my ceiling damp but the roof looks fine?
Water often travels along timbers and underlay before it shows inside, so the visible damp is rarely the entry point. We inspect the roof to trace the true source rather than patching the symptom.
Can you find a leak with a drone?
Yes. A drone survey gives clear, close-up imagery of tiles, flashing, chimneys and valleys, which often reveals the source of a leak without needing scaffolding for an initial inspection.