liquid-roofContrary to popular belief, the flat roof is not necessarily a lower-quality feature, and isn’t necessarily more prone to leakage. If installed by a professional, a flat roof can last several decades, and can withstand everything the British weather has to throw at it.

The problem with flat roofs is that they are vulnerable to poor installation, and they deteriorate quickly if incorrectly pitched. Here are a few ways to stop your roof from developing a leak.

Troublesome Areas

In the UK, flat roofs tend to be relatively small, often over an extension or garage. This means they are quite inexpensive to make. The roof is supposed to be sloped enough to allow water to run away, with a membrane keeping the roof waterproof.

The inexpensive nature of flat roofs has lead to some ‘cowboy’ companies cutting corners, failing to insulate the roof properly and not installing sufficient support beneath the membrane. If a roof does not have the correct structure underneath in the decking, this can cause the membrane to sag when it rains or snows, stretching the joints and encouraging holes.

Roofs can also leak if the gravel layer on the flat area is scraped away or disturbed by someone walking on it, or if the guttering blocks and causes water to back up. Felt roofs are also notorious for developing tiny holes.


Preventing a leak is a three-stage process.

  • First, you must ensure quality installation of the roof. If you’ve moved into a home with a flat roof, it’s wise to get it inspected for faults straight away. This is especially important if you see any water marks or sagging.
  • Second, inspect the roof frequently. Get as close as you can without walking on it. Look for seals that have lifted, signs of wear or rainwater pooling on the surface.
  • Finally, check inside your home, under the roof. If you spot signs of water damage or damp, it could be a sign that water is trickling through.


To repair a leaking flat roof, South Thames Roofing uses a number of proven products and techniques. The approach will be dictated by the location of the damage, the extent of the hole, and the length of time the damage has been present. Often, a tiny hole results in a surprising amount of damage because it goes unnoticed for so long.

Our fitters use PVC or EPDM (ethylene propylene diene monomer) synthetic rubber membranes in order to better waterproof the roof. PVC roofs are great for energy efficiency, while EPDM can last more than thirty years if fitted correctly. These membranes are usually laid in sections and bonded using a hot torch or special tape. This is why quality of installation is critical to the longevity of a flat roof. The more time and care is taken over the shaping and bonding, the better the roof will be, and the longer it will last without a new leak appearing.

Get it Inspected

Our team will inspect your flat roof, diagnose the problem and tell you how we will fix it so it won’t return. We don’t cut corners, botch a solution, or charge you for repairs you don’t need.

If you suspect a problem, call South Thames Roofing now. The longer you leave it, the worse it will get.