The short answer
A Finlock gutter is a precast concrete gutter built into the eaves of a house, so the roof edge and the gutter are one structure. Finlock is the name of one such system, and it is found on some older houses. When these gutters fail, they leak into the wall. Repair, lining and replacement are all options, and replacement averages £2,400 as a typical UK figure (MyJobQuote, Jan 2026).
Not a plastic gutter on brackets, but a concrete channel set into the wall head. That changes how it fails and how it is fixed.
What a Finlock gutter is
Most guttering hangs from the fascia on brackets. A concrete gutter system does not. The gutter is a precast concrete channel, laid as part of the eaves at the top of the wall, with the roof sitting back from it. There is often no visible fascia board at all, just a concrete lip and a downpipe at the end.
Why is it called Finlock?
Finlock is a trade name for one such system, and in everyday talk it has come to stand for the whole kind. If your house has a deep, boxy gutter that seems to be part of the wall rather than hung from it, that is the pattern to look for.
The design has a built-in weakness. Because the channel sits in the structure, water that escapes does not drip to the ground. It soaks into the brickwork and the ceiling edge. The gutter is also heavy, so working on it is a job for people who know what they are handling.
For ordinary hung guttering, our page on repairing or replacing guttering is the right place to start, and the cast iron gutter repair page covers the heavier metal kind.
How concrete gutters fail
Concrete is hard and long-lived, and these gutters still go wrong in predictable ways.
What are the signs of a failing concrete gutter?
Look for damp staining down the wall below the gutter, green growth along the face, cracks in the concrete, and water spilling over a section instead of reaching the downpipe. Indoors, a mark high on an outside wall, where it meets the ceiling, can be the first sign. In a heavy downpour you may see water coming through the joint between sections.
The causes are mostly ageing. The joints between the precast sections open as the building moves, and the waterproof lining or sealant that was once there gives up. Reinforcing steel inside the concrete can rust if water reaches it, and as it rusts it swells and breaks off pieces of concrete. Blocked outlets make everything worse by letting the channel fill and overtop.
Because the gutter and the wall are one, a small leak left for years can mean damp brickwork and rotten roof timbers behind. A survey should look at the wall and the roof edge, not only the channel.
Lining, repair or replacement
Which route suits your house comes down to the state of the concrete, and the three options differ a lot.
Can a concrete gutter be lined instead of replaced?
Sometimes. If the concrete is sound and the problem is the joints or the waterproofing, a new lining can seal the channel and give it further life. It leaves the structure alone and is the lighter job. It is not the answer for cracked concrete or exposed, rusting reinforcement, where the lining has nothing sound to bond to.
Replacement means taking out the concrete channel and fitting a new gutter system in its place, often a hung gutter on a new fascia with the roof edge rebuilt to suit. MyJobQuote gives an average of £2,400 for concrete gutter replacement as a typical UK figure (MyJobQuote, Jan 2026). Access, the length of run and what is found behind the old gutter move that up or down.
Repairs to sections, outlets and joints sit in between. A small, local failure can often be mended without touching the rest. Our page on leaking gutter joints covers the sealing side for ordinary systems.
How we look at a concrete gutter job
Scaffold or a tower is needed, because a ladder is not a safe base for lifting or relining a heavy channel. We look at the gutter from close range, check the wall and the roof edge for damp and rot, and photograph the wall and the channel so you can judge the damage for yourself.
What do you decide at the survey?
Whether lining is realistic or the concrete has gone too far. If it has, we explain what replacement involves, including how a new gutter would sit against the roof and wall. A lining is only proposed where the gutter can hold it.
One total price is then put in writing. A concrete gutter job may also involve the roof's bottom course, the eaves felt and the wall finish, so the survey covers those too. It is worth knowing what the wall looks like before deciding between lining and replacement.
If you have a house of this kind and see staining on the wall or water over the lip, ask for a survey. The main gutters, soffits and fascias page lists everything else we do at the roof edge, and the form takes a photo from the ground if you have one.
More on concrete gutters
Is a Finlock gutter the same as a cast iron gutter?
No. Cast iron gutters hang from brackets or the fascia and can be repaired or swapped section by section. A Finlock-type gutter is concrete and built into the eaves. Different materials fail differently, so the repair route differs too. Our cast iron gutter repair page covers the hung kind, and this one is about the concrete channel.
Does a concrete gutter leak into the house?
It can. Because the channel is part of the wall head, escaping water goes into the brickwork and roof timbers rather than onto the ground. A stained ceiling edge or damp patch high on a wall is a reason to have the gutter and the roof edge looked at together.
The full picture: Gutters, soffits and fascias in Taunton · More short answers