Why does my roof only leak during heavy rain?
The short answer
A leak that only shows in prolonged downpours usually points to volume rather than a straightforward hole. Valleys, gutters and outlets that cope with ordinary rain can overwhelm in heavy rain and back water up under coverings. Underlay defects behave the same way — they shed a little water and fail once saturated.
What evidence should you look for?
Gutters overflowing, or water visibly running over the fascia during a downpour.
- What it can mean
- Drainage capacity is being exceeded and water is reaching the roof edge.
- What else could explain it
- Partially blocked outlets can behave normally in light rain and overflow only under load.
Investigate · Inspection needed to confirm
What could this mean?
The test is repeatability. If it happens in every sustained downpour and never otherwise, look first at how water is being collected and discharged, not for a hole in the slope.
Related services
- Fascias, Soffits and GutteringThe roofline — fascias, soffits, bargeboards and guttering — carries rainwater away from the building and closes off the eaves. When it fails, water runs down the walls and into the wall head, causing damp and rot far below the roof itself.
- Roof RepairsA roof repair fixes a localised fault — slipped slates, cracked tiles, failed flashing, a leaking valley or a split flat-roof seam — without replacing the whole roof. Most Cumbrian domestic repairs are completed in a single visit once the true cause of the leak has been identified.
What should you do next?
Watch the roof safely from the ground during heavy rain and note where water overshoots, ponds or backs up. That single observation often locates the problem.
Reviewed by Aaron, Owner, Elite Roofing Services Cumbria Ltd — last reviewed .
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