So, you’re thinking of painting your flat roof with a ‘miracle’ coating?

I get this question a lot from homeowners in Brighton and Hove. You’ve got a small leak or your old felt roof looks a bit tired, and you see a tin of ‘liquid rubber’ or ‘roof seal’ at the DIY shop. It seems like a cheap, easy fix. Let me give you the straight, honest answer you won’t get on the packaging: it’s almost always a bad idea.

Can I just paint over my old felt flat roof?

The short answer is yes, you *can*. You can go out, buy a product like Acrypol or a bitumen-based paint, and slather it on. For a few weeks, it might even seem to stop the leak. But you haven’t fixed anything. You’ve just put a plaster on a broken bone.

Here’s the problem: that coating is just a thin layer hiding the real issue. The original roof underneath is still failing. Moisture can get trapped between the old roof and your new coating, accelerating rot in the timber decking beneath. When it inevitably fails again, it’s a messier, more complicated job for a professional to sort out because I have to strip off your sticky DIY layer first.

What are the biggest risks of a DIY roof coating job?

I’ve seen some real disasters across Worthing and Sussex from well-meaning DIY attempts. The biggest risks are:

  • Trapping Moisture: This is the number one problem. If you paint over a damp roof, you’re sealing the water in. This leads to timber rot, mould, and structural issues that are far more expensive to fix than the original leak.
  • Poor Preparation: A roof needs to be bone dry and surgically clean for any coating to have a chance of adhering. Most people don’t have the equipment or patience to do this properly, so the coating just peels off in a few months.
  • You Miss the Real Problem: That drip in your ceiling might not be coming from where you think. It could be a failed flashing, a problem with a brick wall, or a blocked gutter. Painting a random patch on the roof won’t solve it. If you have an active drip, you need to deal with an urgent roof leak properly by finding its source.

So, how do I *actually* fix a failing flat roof?

When I’m called out to a job in Brighton, I don’t bring a bucket of paint. A professional fix involves a proper diagnosis. I find the source of the water ingress, strip back the failed material, inspect the wooden roof deck for any rot or damage, and then install a brand new, robust waterproofing system. This could be a modern high-performance torch-on felt system or a seamless GRP fibreglass system. This is the only way to guarantee a long-term, watertight solution. You can read about the proper methods on my page for flat roof repair and replacement services.

What about my garage or rear extension roof? Is a coating okay for that?

No. The principle is exactly the same. Your garage roof protects your car and possessions; your extension roof is part of your home. Cutting corners here is a false economy. A small leak can quickly damage the contents of the garage or the ceiling and electrics in your extension. The only correct way to fix a failing roof is with a proper garage flat roof replacement or a new, professionally installed rear extension flat roof. Don’t gamble with it.

My final advice on flat roof coatings

Look, I understand the temptation to find a quick, cheap solution. But a tin of paint is not a new roof. It’s a temporary patch at best and a costly mistake at worst. You’re far better off understanding the true condition of your roof and getting a proper, permanent fix.

If you’re in Brighton, Hove, or Worthing and you’re worried about your flat roof, don’t reach for the paintbrush. Instead, book a free, no-obligation roof inspection with me. I’ll get up there, take a proper look, and give you an honest assessment and a fixed-price quote. You’ll even get access to my client portal with daily photo updates if we go ahead with the work. It’s the right way to do it.