Your Questions About Slate Roof Repair, Answered Honestly

Slate is a fantastic roofing material. It looks brilliant, especially on the period properties we have all over Brighton and Hove, and it can last for over a hundred years. But it’s not invincible. Sooner or later, you’ll face a slipped or broken slate. Here’s my straight-talking advice on how to handle it, based on 18 years of working on these roofs.

What are the first signs my slate roof needs repairing?

Don’t wait for a drip to appear on your ceiling. The early signs are usually outside. Keep an eye out for:

  • Slipped Slates: You’ll see one or two slates that have slid down, breaking the clean line of the roof. This is the most common call-out I get in Worthing and Brighton.
  • Bits in the Gutter: When you’re checking your gutters, look for small, sharp pieces of slate. This means something has cracked or shattered up top.
  • Cracked Slates: You might not see these from the ground, but a cracked slate is a leak waiting to happen.
  • Daylight in the Loft: On a bright day, pop your head into the loft. If you see pinpricks of light, you’ve got a hole somewhere. If it’s this bad, you might have an urgent leak on your hands.

I’ve found a slipped slate. Can I just push it back up?

Absolutely not. It’s the worst thing you can do. A slate doesn’t slip for no reason. It slips because the nail holding it in place has rusted through and failed. This is called ‘nail sickness’. Pushing the slate back up does nothing; there’s nothing to hold it there. It will just slide back down with the next bit of wind or rain.

A proper temporary fix involves inserting a copper strap, called a ‘tingle’, to hold the bottom of the slate in place. The permanent fix is to remove the slates around it and re-nail a new one. Don’t just stick it back with silicone – that’s a bodge job that traps water.

Can I repair a cracked slate tile myself?

Look, you *can* get a tube of roofing silicone or a paint-on repair product and smear it over the crack. I’m not going to pretend you can’t. It might even stop a small drip for a few weeks, maybe even a few months if you’re very lucky.

But here’s the hard truth: it’s a sticking plaster on a broken bone. Water will eventually get under the patch, get trapped, freeze, and make the crack even bigger. You’re just delaying the inevitable and potentially causing more damage. The only correct way to fix a broken slate is to replace it entirely.

How do you properly replace a broken slate?

This is where experience and the right tools come in. I use a tool called a slate ripper – a long, thin, hooked blade. I slide it up under the broken slate to hook onto the nails holding it and rip them out. Then, the old slate slides free.

I then slide a new, matching slate into the gap and secure it with a single copper nail in the vertical joint between the slates above it. I also add a copper tingle for extra security. It’s a precise job, and doing it wrong can break the surrounding slates.

What’s ‘nail sickness’ and is it a big deal?

It’s the number one killer of old slate roofs.

The original roofers used iron or galvanised steel nails. Over 70-100 years, especially with the salt air we get in Sussex, those nails corrode and fail. The slate itself might be fine, but with nothing holding it, it slips out. If you have one or two slipped slates, it’s a simple repair. If you’re seeing five, ten, or twenty, it’s a sign that the entire roof’s fixings are failing.

At that point, patching it up is a false economy. You’re just chasing your tail. This is when you need to start considering a full pitched roof replacement, where we strip the old slates, install a modern breathable membrane, new battens, and then re-fix the slates with new copper nails. It’s also a good time to check other elements like the lead flashing around chimneys.

Think you have a slate roof problem?

Don’t guess. A small issue with a slate roof can become a big, expensive one very quickly if it’s ignored or bodged. The best thing you can do is get an experienced eye on it. I can tell you in minutes whether you’re looking at a simple repair or a more serious issue.

I provide fixed-price quotes and you can book a proper roof inspection right on my website. I’ll even set you up with a client portal so you can see daily photos of the work. No jargon, no hidden costs, just honest work.