If you’ve got a damp patch on a bedroom ceiling, a drip in the loft after heavy rain, or a stain that runs down an inside corner, there’s a good chance the problem is your roof valley. Valleys are one of the most common places for a roof to leak, and one of the most often misdiagnosed.
We recently repaired a leaking valley on a tiled roof here in Ely, and it’s a good example of what goes wrong and how to fix it properly. Here’s what we found, what we did, and what to look out for on your own home in Ely, Littleport, Soham, Sutton, Stretham and across Cambridgeshire.
What is a roof valley?
A valley is the internal corner where two sloping roofs meet, usually where an extension, dormer or L-shaped section joins the main roof. Rain from both slopes runs into it, so a valley carries far more water than any other part of the roof.
That’s exactly why it fails. When a valley is blocked, worn out or badly built, all that water has nowhere to go but under the tiles and into your home.
Signs your roof valley is leaking
- A damp patch or brown stain on a ceiling near an inside corner of the house
- Drips or wet timbers in the loft after heavy rain
- Moss, leaves and debris built up along the valley line
- Cracked, slipped or badly cut tiles either side of the valley
- Water overflowing at the bottom of the valley instead of draining into the gutter
The job: a leaking valley in Ely
When we got up on this roof, the cause was easy to see. The valley line was packed with moss and debris, and years of weather had broken down the old valley underneath. Water was no longer running cleanly down to the gutter. It was backing up and getting under the tiles.
Patching it with sealant would only have bought a few months. So we did it properly:
1. Stripped the old valley
We carefully lifted the tiles either side and removed the old, failed valley completely, so we could see the timbers and battens underneath.
2. Laid a new breathable membrane
A new breathable roofing membrane went down the full length of the valley. It’s a second line of defence against driven rain, while still letting moisture escape from the roof space so you don’t end up with condensation in the loft.
3. Fitted the new valley
The new valley went in on top, giving the water a clean, continuous channel all the way to the gutter.
4. Cut the tiles in straight
Finally, we re-laid and cut the tiles in neatly and straight along both sides. Tidy cutting isn’t just about looks: a straight, even line keeps water flowing into the valley, rather than tracking sideways under the tiles.
The result is a valley that sheds water the way it’s meant to. No more drips, no more stains, and no need to go back up with the sealant gun every winter.
Why roof valleys fail
Most valley leaks we see across Ely and the Fens come down to a few things:
- Blockages. Moss, leaves and debris build up and dam the water. It’s especially common near trees.
- Age. Older valleys and underlays simply wear out after decades of sun, frost and rain.
- Poor installation. Short valleys, missing membranes or badly cut tiles let water creep in from day one.
- Storm damage. Strong winds can lift tiles along the valley edge and let rain blow straight in. Out on the open Fens around Ely, Littleport and Prickwillow there’s not much to slow the wind down, so wind-driven rain is a real test for any valley.
The Met Office recommends checking your roof for loose tiles, slates and flashing before winter arrives. Valleys should be top of that list.
Roof valley repair or full re-roof?
In most cases a roof valley leak repair can be done on its own, without replacing the whole roof. We’ll always tell you honestly which you need. If the tiles and battens elsewhere are sound, a valley repair is usually the quickest and most cost-effective fix.
If the roof is showing wider problems, such as slipped tiles all over or a sagging structure, it may be worth looking at our pitched roof or roof renovation options. Some homeowners also ask about lighter replacement systems, and our guide to Britmet lightweight roofing in Ely explains when that makes sense.
Blocked gutters at the bottom of a valley can make a leak much worse, so we’ll also check your fascias, soffits and guttering while we’re up there.
Don’t leave a valley leak until spring
A small valley leak rarely stays small. Water that gets in can soak insulation, rot battens and rafters, and damage plaster and decorations below. The longer it runs, the bigger and more expensive the repair.
If you’re thinking about an insurance claim for storm damage, get the roof looked at quickly and keep photos of the damage. Insurers usually separate sudden storm damage from gradual wear and tear, so a prompt inspection and a clear report from a roofer can really help.
Choosing a roofer in Ely you can trust
Whoever you use, check they’re experienced with pitched roofs, can show you photos of their work, and will explain clearly what’s wrong before they start. Trade bodies such as the National Federation of Roofing Contractors (NFRC) and the government-endorsed TrustMark scheme have useful guidance on choosing a reputable tradesperson.
At Ely Roofing Company we’re a local roofer based in Littleport. All our work is guaranteed and we never ask for upfront payments or deposits. You can read more about us or see what customers say in our reviews.
Roof valley leak repair in Ely, Littleport, Soham and Cambridgeshire
We carry out roof repairs across Ely, Littleport, Soham, Sutton, Stretham and the surrounding villages. If you think your valley is leaking, or you just want it checked before winter, get in touch.
📞 Office: 01353 861590
📱 Call or WhatsApp: 07970 753613
âœ‰ï¸ Or send us a message on our contact page
Roof valley and roof leak FAQs
Why do roof valleys leak?
A valley takes the rain from two slopes at once, so it works harder than any other part of the roof. Most leaks come from moss and leaves blocking the channel, an old valley that’s simply worn out, mortar that’s cracked, or tiles either side that weren’t cut in properly. Fix the cause, not just the drip.
Why does my roof valley only leak in heavy rain?
In light rain the valley copes. In a downpour, or when wind drives rain across the Fens, the water backs up faster than the valley can carry it away, especially if it’s partly blocked or the gutter at the bottom is full. It then spills over the edges and under the tiles. A leak that only shows in heavy rain is a warning sign, not something to wait on.
How do you fix a leaking roof valley?
On a proper repair we lift the tiles either side, strip out the old valley, lay new breathable membrane, fit a new valley and cut the tiles back in straight. Sealant or a quick patch from the ground might stop it for a while, but it won’t last through an Ely winter.
How much does a roof valley repair cost in the UK?
It depends on the length of the valley, what it’s lined with (lead, GRP fibreglass or a dry valley system) and whether scaffolding is needed. We don’t guess over the phone. We’ll come out, have a look and give you a free, no-obligation quote, and the price we give is the price you pay.
Lead, GRP or dry valley: which is best?
Lead is the traditional choice and lasts the longest, which suits older and period roofs in and around Ely. GRP (fibreglass) and dry valley systems are lighter, cheaper and have no scrap value, so they aren’t a target for thieves. The right one depends on your tiles, the pitch and the age of the roof, and we’ll tell you honestly which we’d use and why.
Can a roof valley be repaired without replacing the whole roof?
Usually, yes. We only work on the valley and the tiles either side, so the rest of the roof is left as it is. If we think the whole roof is near the end of its life, we’ll say so and show you why.
How long does a roof valley repair take?
Most valley repairs on houses in Ely, Littleport and Soham are done in a day, depending on the length of the valley and the weather.
What should I do if my roof is leaking right now?
Put a bucket or tray under the drip, move anything valuable out of the way and, if it’s safe, take a few photos. Don’t climb on the roof yourself. Then ring us on 01353 861590 or WhatsApp 07970 753613. The stain on your ceiling isn’t always right under the problem, as water can run along the battens first, so it’s worth getting it traced properly.
Can a roof leak be repaired in the rain?
A full valley repair needs dry weather, because the tiles have to come off. In wet weather a roofer can often make the leak safe for the time being, then come back and do the proper repair once it dries up.
Is a leaking roof covered by home insurance in the UK?
It depends on your policy and the cause. Sudden storm damage is often covered by buildings insurance, while gradual wear and tear, like an old valley that’s slowly failed, usually isn’t. Check with your insurer, keep photos, and get the roof looked at quickly so the cause is clearly recorded.