Roof leaks in schools are never something to ignore. When water starts making its way into classrooms, it quickly becomes more than just a roofing issue, it’s a disruption to the building, the staff, and the students inside.
In this job, I was called out to investigate a leak on the first floor of a school building in Long Eaton Nottinghamshire, directly below a roof valley. Valley leaks are a common culprit in these situations, and as you’ll see, getting the diagnosis right is just as important as the repair itself.
If you want to see exactly how this repair was carried out at height using a cherry picker, you can watch the full video here.
Investigating the Leak: Why Valleys Are Often the Problem
The leak was showing internally beneath a valley where two roof slopes meet. Valleys take a huge amount of water during heavy rain, so any weakness in the leadwork tends to show up quickly inside the building.
Once I was up in the cherry picker and able to inspect the valley closely, it was clear this wasn’t the first time the roof had problems. The lead had been repaired before and was in poor condition, with visible cracking in more than one section.
Ideally, the best long-term solution would be to strip out the entire valley and replace it. However, that simply isn’t practical from a cherry picker. A full replacement would require removing a large number of tiles and would be far more suited to scaffold access.
The key here was finding a durable repair solution that could be completed safely, efficiently, and properly with the access available.
Choosing the Right Repair Method (Not Just the Quick Fix)
The internal damage lined up perfectly with the cracked lead sections I could see externally. That gave me confidence that I was dealing with the correct source of the leak.
Rather than applying surface-level fixes like flashband or simply smothering sealant over the cracks, I opted for a more permanent approach:
- Strip back only the tiles necessary to access the damaged area
- Cut out the cracked lead sections
- Slide new lead underneath the existing valley lead
- Lap it correctly so water naturally sheds down the roof
This method effectively creates a new watertight layer beneath the damaged section, without needing to dismantle half the roof.
It’s the kind of repair that, while not a full replacement, should last as long as the roof itself or at least until the building is eventually re-roofed.
A Quick Safety Lesson from the Job
This wasn’t the first time I attempted to film this repair. The original attempt ended early due to a mistake that’s worth sharing.
While cutting lead, I slipped and badly cut my finger by cutting towards myself with a knife. It was entirely my own fault and exactly the sort of mistake we all know better than to make, yet still sometimes do.
The reason I mention it is simple: if sharing that moment makes even one person pause and think about knife direction and hand placement, it’s worth saying. On roofs, small lapses can quickly turn into injuries.
Working With What You Have on the Day
Another challenge on this job was material size. The lead available wasn’t quite wide enough to complete the repair in a single piece while maintaining ideal side overlaps.
To solve this properly, I installed the new lead in three overlapping sections:
- One central strip
- Two side strips, each giving at least a 100mm overlap
Once sealed and dressed down, this provided excellent coverage. With the tiles reinstated, the repair was fully protected and watertight.
Sometimes roofing isn’t about perfect conditions it’s about making sound decisions with the tools and materials you have on site.
The Finished Repair – And Why Diagnosis Matters Most
With the old lead folded back, tiles reinstated, and the new lead fully dressed in, the valley repair was complete. This should stop any further water ingress into the room below.
Leaks in corners of rooms, especially where two roofs meet are very often caused by:
- Cracks in lead valleys
- Small holes forming over time
- Failed historic repairs
There are many ways to stop a valley leaking temporarily, but sliding new lead beneath cracked sections is one of the more reliable repair methods when replacement isn’t practical.
Ultimately, the most important part of any roofing job is correct diagnosis. Once you know exactly where the water is getting in, the repair becomes much more straightforward.
If you’d like to see the full process, including access setup and lead installation, I’d strongly recommend watching the full video.
Final Thoughts
I hope this job breakdown was useful, whether you’re in the trade or just curious about how roof leaks are diagnosed and repaired. If you’ve got experience with valley repairs or a different approach you’ve found effective, feel free to share it in the comments.
And if you want to see more real-world roofing, access, and repair jobs, make sure you follow me online and keep an eye on the next video.
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My workwear is sponsored by Granite Workwear, and all of the clothing I’m wearing in the video can be purchased on their website: Workwear Clothing Supplier | Protective Safety Clothes
