Common Causes of Flat Roof Leaks and How to Prevent Them

Most flat roof leaks come down to three things: poor installation, ageing materials or blocked drainage. Left alone, even a small leak can soak the deck, damage ceilings and lead to much bigger repairs. The good news is that most of them can be prevented.

The common causes

• Blocked outlets and gutters. Leaves, moss and silt stop water getting away. It backs up and finds its way under edges and laps.
• Standing water. If a roof doesn't fall properly to its outlets, puddles sit for days and slowly work at any weakness.
• Failed upstands and flashings. Where the flat roof meets a wall, a parapet or a rooflight is one of the commonest leak points.
• Split or blistered felt. Older felt roofs crack and blister as they age, especially after years of sun and frost.
• Poor detailing at installation. Corners, edges and pipes that weren't finished properly will leak sooner or later, whatever the membrane.
• Damage. Falling branches, foot traffic or items dropped on the roof can puncture the surface.

How to prevent leaks

• Clear outlets and gutters at least twice a year, especially after autumn.
• Have a look at the roof after storms, if you can do so safely from a window or ladder.
• Keep foot traffic off the roof unless it's designed for it.
• Get small problems repaired early, before water reaches the deck.
• When the roof needs replacing, choose a system and an installer that get the details right.

Finding the leak

Water travels, so the drip inside isn't always under the hole outside. Part of a proper repair is tracing where the water is actually getting in, rather than patching the first thing that looks wrong.

Ayre Roofing repair EPDM, GRP and felt flat roofs across Exeter, Chudleigh and Newton Abbot, and we can advise on drainage and waterproof coatings to stop leaks coming back. Repairs carry a 1-year guarantee and new roofs a minimum of 5 years.

If your flat roof is leaking, call 07803 365 251. Depending on scheduling and materials, we may be able to help the same day. See our roof repairs page for more.