Finding a flat roof leak is detective work. The drip inside is rarely below the hole, so we work methodically from the stain back to the true source.
Ashley Down has many flat roofs on rear extensions, bay tops and porches added to Victorian and Edwardian terraces. When one leaks, the stain on the ceiling may be a metre or more from the real fault. We trace the water first and repair afterwards, because a repair in the wrong place only delays the next call.
Starting from the inside
We begin with the ceiling and any access to the roof space or void above. We look at where the stain is, how it spreads, whether it grows after rain or stays damp, and whether the insulation or timber is wet. Water travels along joists and under the deck, so the stain only shows where it finally finds a way out.
Looking at the surface
Outside, we inspect the whole covering, not just the area above the stain. We look for splits and cracks, blisters, lifting seams and sealed joints that have failed. Edges, trims, gutters and outlets are checked. We also look at upstands where the roof meets a wall, a common entry point on extensions built against older brickwork.
- Cracks, splits or worn patches in the covering
- Blisters that have burst or lifted
- Failed joints around pipes and rooflights
- Blocked outlets and standing water
Testing and confirming
If the cause is not obvious, we narrow it down: checking after rain, isolating sections, or using controlled water tests from the ground up, starting low and working higher so the entry point shows itself. We would rather spend a little more time confirming than guess. Once we know where it enters, we can explain what is wrong and show you. On extensions with several junctions this stage is often what makes the repair last.
Repair or something bigger
A local fault in a sound roof is repaired: a split sealed and patched, an upstand re-formed, an outlet cleared or replaced, a trim refitted. If the deck underneath is wet or rotten, it needs cutting out and renewing before the surface is touched. Where the covering is failing across a wide area, replacement is better than a string of patches.
What you can do before we visit
Note when it leaks, take photographs of the stain, and check the gutter and any outlet from the ground. Keep items clear of the area, and place a container if it drips. Do not climb up to look, as flat roofs may be slippery and deck damage is hidden. Call us for a proper look, and we will explain what we find and what the options are.
Frequently Asked Questions
Why does my flat roof only leak after a lot of rain?
Small splits and weak joints may only let water through when the roof is saturated or when water stands on it. Poor drainage or a blocked outlet makes that worse, which is why we check falls and outlets.
Can a flat roof leak be fixed from inside?
Not properly. Inside repairs only deal with the damage, such as stained plaster. The roof covering must be repaired from outside, once the entry point has been found and the deck checked. Until then the stain may keep returning.
How do you know the deck is sound?
We look at the underside where possible and check the feel and condition of the deck when the covering is opened. Soft, dark or spongy timber is cut out and replaced before any new covering goes down, and we show you what we removed.
Talk to our team about flat roofing in Ashley Down
Every roof is different — the fastest way to get an accurate answer is a quick chat with our team.