Question answered
Is it the gutter or the roof that is leaking?
The short answer
Look at when and where the water appears. A gutter fault shows during or just after rain at the eaves, down an outside wall or on a ceiling next to the external wall, and overflow marks the face of the wall. A roof fault tends to show further in, on ceilings below the slope or around a chimney, and sometimes only once the rain has gone. Both can happen at once.
A damp patch on a wall or ceiling can come from the guttering or from the roof covering above it. Where the water shows, and when it shows, usually points to which.
Watch the gutter while it rains
The simplest test costs nothing. Wait for steady rain, put a coat on and look at the guttering from the garden. A healthy gutter carries the water along to the downpipe. A faulty one shows its problem openly: water spilling over the front lip, dripping from a joint, pouring down the wall behind it or leaving the downpipe dry because the outlet is blocked.
Overflow is the usual cause of damp on an outside wall. Water that ought to be moving gets held by a blocked outlet, a sag between brackets or too little fall. A fall is the slight slope towards the outlet; manufacturers typically recommend a gentle one, roughly 1:600 to 1:350 depending on the system, and a sagging run loses it.
If the water is going over the front, the wall below gets a stripe of green or dark staining and the paint blisters in that line. If it is running behind the gutter, the damp appears higher up, at the fascia, soffit or the top of the wall, and can look very like a roof fault.
Where the damp sits tells you a lot
Look at the position of the mark rather than its size. A stain along the top edge of an external wall, directly below the eaves, suggests water getting behind the gutter or fascia. A patch that runs down the outside of a wall below a joint or corner points to a leaking union or downpipe.
A stain in the middle of a ceiling, or on the sloping part of a room in the roof, is more often the covering itself: a split tile, a dropped slate or a lifted flashing, the metal strip that stops water at the joint between roof and brickwork. A brown ring beside a chimney breast usually leads the eye upwards to it.
Water travels. It slides down a rafter or along the underlay and falls elsewhere, so the stain sits away from the fault. That is why we follow the damp back to where it starts instead of treating the spot you can see. Our page on what a loss adjuster looks for explains why a clear record of the pattern matters if you claim.
Checks from the loft
Should the loft be reachable without risk, take a torch up during or just after rain. Check the roof's underside for drips and shine, and the timbers for dark, wet patches. Follow each one upwards to the highest wet point, since the entry is usually higher than the mark.
Look at the eaves too. If only the wood right at the eaves is wet and the rest of the loft is dry, the problem is probably the gutter or the fascia. If the wet is along a rafter higher up, a hip, a valley or around a chimney, the covering is more likely. Wet along the wall plate, the timber that carries the rafters, hints at overflow over a long period.
Condensation can mimic a leak: warm, damp air from the house meeting cold timbers can leave droplets and black mould with no hole anywhere. A mark that comes in cold weather with no rain behind it deserves a different explanation. Stay off the roof itself, and keep to the boards if you step in the loft.
What can be done without a roofer
Gutter faults are often within reach of a careful householder at ground level. Clear leaves from outlets you can safely reach from a stable ladder, check that downpipes are carrying water, and look for joints with dried-out seals. Moss and silt that builds up along a gutter will hold water back in the next storm.
Stay off high roof edges when it is wet or blowing, and never rest the ladder on the gutter itself. A gutter with failed brackets, cracked sections or a rotten fascia needs a repair or replacement, and long runs are best left to someone with proper access.
The roof covering is a different matter. Tiles, slates, ridges and lead need to be looked at from above, safely, by someone who can recognise the faults. Leaks and storm damage get our priority, and the roof is made safe first. If the damp is still coming through after the gutter is clear, the next step is a survey rather than more guesses. A temporary cover is explained on our roof tarpaulin page.
When the answer is both
Gutters and roofs fail together more often than the two-way choice implies. A slipped tile at the eaves puts water straight into the gutter run, and an overflowing gutter soaks the felt and the bottom of the roof at the same time. A fallen branch or a tree on the roof can break tiles and crush the gutter in one event; see what to do about a fallen tree on a roof.
Fixing one without the other is a common reason for a leak returning. We follow the water back along its whole path and photograph the result. You receive one written total, and the photographs show which part is at fault.
The wider range of urgent work is on our emergency roof repairs page. Roofline work, meaning the gutters, fascias and soffits together, usually makes sense when the timber behind the gutter is damaged. Where only a joint or a length of gutter has failed, a smaller job properly done is enough, and that is the repair we recommend.
Gutter or roof, two more questions
Why is my outside wall damp only under the gutter joint?
A leaking joint drips onto the same strip of wall every time it rains, which soaks the brickwork and can show inside as a patch on the wall. It is normally a failed seal or a misaligned section and is a quick, local repair.
Can a blocked gutter cause a ceiling leak?
Yes, indirectly. Overflowing water can run behind the fascia, wet the eaves timbers and the bottom of the roof covering, then show as a stain on the ceiling near the outside wall. Clearing the gutter is the first step, with a survey if the stain keeps coming back.
Tell us about your roof
Describe what is happening and we will call you back to arrange a visit.
- Photographs of what we find
- A written quote with one total price
- Or call 01903 299063
10-year workmanship guarantee, in writing.