If you’re asking yourself why your roof is leaking, the honest answer is that it’s almost always one of a handful of things. A tile has slipped, the flashing around a chimney or valley has failed, the gutters are blocked, or the felt underneath your tiles has simply worn out with age. Working out which one applies to you usually means a proper look at the roof itself, ideally from someone who does this for a living, but knowing the common culprits helps you understand what a roofer is likely to find and why it happened in the first place.

At JP Roofing, we’re regularly called out across Hailsham and East Sussex to trace leaks that homeowners have been battling for weeks. Below we’ve set out the most common causes, how to narrow down where the water is actually getting in, and when it’s worth picking up the phone rather than reaching for a ladder yourself.

The most common causes of a leaking roof

Slipped, cracked or missing tiles

Wind is the biggest culprit here. Once fixings age or a tile cracks, it can shift out of place and leave a gap for rain to get underneath. A missing tile is often easy to spot from the ground after a storm, but a cracked one that’s still sitting in place can be much harder to notice until water has already found its way in.

Failed flashing around chimneys and valleys

Flashing is the metal, usually lead, that seals the joins where your roof meets a chimney, wall, or valley. These junctions are naturally weak points, and once the lead lifts, cracks, or the pointing around it crumbles, water gets a direct route into the roof space. Our leadwork team deals with this more than almost anything else, particularly on older properties around East Sussex where the original lead is decades old.

Blocked or damaged guttering

When gutters fill with leaves and debris, water has nowhere to go except over the edge and back up under the roof covering. It’s one of the simplest problems to prevent and one of the most common to find once you actually get up there. If your guttering hasn’t been cleared in a while, that’s worth ruling out before assuming the worst about the roof itself.

Cracked pointing on ridge tiles

The mortar that bonds ridge tiles together, known as pointing, dries out and cracks over time. Once it fails, wind driven rain can get straight underneath the ridge line. This is a very common finding on roofs over about fifteen years old, and our re pointing service exists largely to deal with exactly this.

Ageing roof felt or underlayment

Underneath your tiles or slates sits a waterproof membrane that catches anything that gets past the outer layer. Like any material, it degrades with age, particularly if it’s been exposed to UV light through gaps or has never been replaced since the roof was built. Once it starts to perish, leaks can appear even when the tiles above look perfectly fine.

Condensation, not a leak at all

Sometimes what looks like a leak is actually condensation building up in a poorly ventilated loft. Warm, moist air from the house rises and meets the cold underside of the roof, and the resulting moisture can drip and stain a ceiling in much the same way rainwater does. If the damp patch only ever appears in cold weather rather than during rain, poor loft ventilation is worth ruling out.

Why UK roofs are so prone to leaking in the first place

It isn’t your imagination. The UK sees rain or snow on an average of 159 days a year, based on Met Office data from 1991 to 2020, and that constant cycle of wetting and drying is exactly what wears out seals, flashing, and pointing faster than in drier climates. Add in the freeze and thaw cycles of a British winter, where water that’s crept into a small crack expands as it freezes and widens the crack further, and it’s easy to see why even a well built roof needs regular attention.

How to trace where a leak is actually coming from

Water rarely drips straight down from where it enters. It tends to travel along rafters, battens, or the underside of the felt before finding a gap in the ceiling to come through, so the damp patch you can see is often some distance from the real source. Checkatrade’s guide suggests marking the spot with chalk and taking measurements from a fixed point like a chimney stack, so a roofer can work backwards from there to find the entry point from outside.

If it’s safe to do so, checking the loft during heavy rain can help you spot the trail as it happens. Climbing onto the roof itself isn’t something we’d recommend doing yourself. It’s higher risk than it looks, and an inexperienced footing can turn a small leak into a much bigger repair.

What to do if your roof is leaking right now

While you’re waiting for a roofer, there are a few sensible steps you can take inside the house. Move furniture and valuables clear of the affected area, and use a bucket or towels to catch any dripping water and protect your flooring.

If a section of ceiling is visibly bulging with trapped water, Alliance Roofing notes that carefully puncturing the lowest point can relieve the pressure and prevent a sudden, larger collapse, though this should only be attempted if you can do it safely. These are temporary measures only. They buy you time, but the source of the leak still needs a proper repair.

Is a leaking roof covered by home insurance?

It depends entirely on the cause. Sudden, unexpected damage, like a storm ripping tiles off an otherwise sound roof, is generally what buildings insurance is designed for. Gradual wear and tear is a different matter and is almost never covered, because insurers see it as a maintenance issue rather than an insurable event.

The Association of British Insurers generally defines storm conditions as wind gusts of at least 55mph or rainfall of at least 25mm within an hour, though individual policies can word this differently. If your roof has been quietly deteriorating for years and finally gives way during a spell of ordinary rain, insurers typically treat that as wear and tear rather than a covered event, which is exactly why keeping on top of maintenance matters as much for your insurance position as it does for keeping the water out.

When to call a professional roofer

A small stain on the ceiling can be tempting to ignore, especially if it dries out between rainfall. But roofs rarely fix themselves, and a leak left unchecked tends to spread into timber rot, damaged insulation, and a much bigger bill than if it had been caught early.

If you’re anywhere across Hailsham or the wider East Sussex area, JP Roofing can carry out a proper inspection and trace the source rather than guessing at it. We cover everything from tiling and slating repairs to leadwork, guttering, and re pointing, so whatever’s causing your leak, it’s one call rather than several different tradespeople. Get in touch through our contact page to arrange a survey.

FAQs

Why is my roof leaking only when it rains heavily?

This usually points to a capacity problem rather than a single obvious gap. Blocked gutters, undersized drainage, or flashing that only lets water through once it’s pooling in volume will often stay dry in light rain and only show a leak once heavy rain overwhelms them.

Can I repair a roof leak myself?

Small, ground level fixes like clearing a gutter are fine to do yourself if you can reach safely. Anything that involves getting onto the roof carries real fall risk, and a repair that isn’t done properly can trap water rather than keep it out, so it’s generally worth having a professional assess anything beyond the basics.

How much does it cost to fix a leaking roof in the UK?

Costs vary hugely depending on the cause, from a straightforward tile replacement through to a full re-felt or flashing overhaul. Get in touch for a survey and we’ll give you an honest, itemised quote once we know exactly what’s causing the leak.

How do I know if my roof leak is an emergency?

If water is actively dripping inside, near electrics, or a ceiling is sagging under trapped water, treat it as urgent and get help the same day. A damp patch that isn’t actively growing can usually wait for a scheduled inspection, though it shouldn’t be left indefinitely.

Will my home insurance pay for a leaking roof?

Only if the cause is a sudden, insurable event such as storm damage. Leaks caused by age, wear and tear, or lack of maintenance are almost always excluded, which is another good reason to have leaks looked at as soon as they appear rather than waiting.