A gutter can look dreadful and still be sound, or look fine from the pavement and be failing along its whole length. The skill is knowing which. Cleaning and a small repair cost very little and suit a run that is basically healthy. Replacement costs more, and is the right call when the material has deteriorated, the fall has gone, or the fixings behind it are failing. This guide lists the signs that point to replacement, explains what lies behind each one, and gives a way to weigh them, so you do not spend a weekend repairing something that is finished or a large sum replacing something that needed an hour.
Cracks and splits in the channel
A crack along the length of a plastic gutter, or a split at a bracket or a corner, is a sign the material has aged. uPVC loses flexibility as it gets older, particularly on south-facing elevations where sunlight and heat work on it every summer. A gutter that has gone chalky, with a powdery surface you can rub off on your finger, will crack when knocked, loaded with wet leaves or put through a frost. One crack can be patched. A gutter with several, or with chalking along the whole run, is worn out, and each repair holds only until the next failure beside it.
Joints that leak in more than one place
A single weeping joint is an everyday fault. A seal hardens, a clip loosens and the answer is a new seal or a replaced union. When joint after joint drips along a run, the seals are all the same age and all failing, and the cost of renewing each one soon approaches that of a new gutter. Look for green or dark streaks on the wall below each joint, for water running down the outside of the pipe, and for icicles that form at joints in a hard frost. Our guide to leaking gutter joints shows how to separate the occasional from the general.
Sagging and standing water
A gutter should fall gently towards its outlet, and water should run out within a short time of rain stopping. If you can see water lying in the trough days after rain, or a visible dip between brackets, the gutter has lost its line. The cause is either brackets that have loosened or snapped, a board that is no longer holding them, or plastic that has softened and drooped. A bracket can be replaced. A dip along the whole run, or one that returns after you correct it, points to a fixing problem behind or to a gutter that has gone limp with age. Our answer on why gutters sag explains the causes in more detail.
Rust, flaking paint and pitting on metal gutters
Cast iron and steel gutters rust from the inside as well as the outside. Flaking paint, orange bloom and small holes in the back or bottom of the trough mean the metal is thinning. Surface rust on cast iron can be wire-brushed, primed and painted, and the gutter lasts for years more. Rust that has gone right through, cracked sections and joints that have seized and split are different. Cast iron is heavy and the failure can be sudden, so a gutter that is cracked or hanging by a few bolts is also a safety matter. On older houses, our page on cast iron guttering on period homes covers repair against replacement.
Brackets pulling out of the fascia
Brackets that keep working loose, or screws that no longer bite, point to the board behind. If the fascia is soft, new brackets will not hold, whatever the gutter looks like. This is the commonest reason a gutter is replaced a second time within a few years, because the fault was never in the gutter. Press a thin blade into the board behind the gutter line. If it sinks in, the board needs dealing with first, and our guide to rotten fascia boards explains how to tell and what to do.
Water marks on the walls
Look at the wall below the gutter in heavy rain, and again the next day. Dark streaks, green algae, a patch of wet brick, blown render or paint, and damp patches inside the room on the other side of the wall all show water running where it should not. Overflow from a gutter that is too small or sagging, leaks from joints, or a downpipe that has come apart will all produce marks like these. A wall that stays wet at the top, under the eaves, and dries from the bottom up is the pattern of a gutter fault. Persistent damp inside should be looked at promptly, because it can damage plaster and timber. Our answer on water running behind a gutter covers a related fault.
Overflowing in ordinary rain
Overflow in a storm can be bad luck. Overflow in a moderate shower means the gutter cannot cope. The cause may be debris, which cleaning cures. It may also be a gutter that is too small for the roof it drains, a run that has lost its fall, an outlet that is partly blocked, or a downpipe that has narrowed. If the gutter is clear and the overflow continues, the design or the fall is wrong. Our answer on why gutters overflow goes through the possibilities, and what size guttering you need explains how capacity is chosen.
Plants, moss and trees in the trough
Small plants growing in the gutter are a sign that silt has built up and held water for long enough for seeds to take root. They are a symptom of neglect more than of failure, and clearing the run will cure them. But if moss, grass or a young sycamore keeps returning within a season, it suggests standing water, which suggests a fall problem. Check the fall with a hose before deciding. The page on moss blocking gutters deals with the roof-side cause.
Gutters pulling away or bowing out from the wall
A gutter that leans out at the top, or has pulled away at one end, is carrying more weight than its fixings can hold. The usual cause is a heavy load of wet leaves, a sagging run, or brackets that have rusted through. If the tiles are catching on the gutter, or the gutter has dragged the felt out of line, the damage may reach the roof edge. Leave this alone beyond a safe look from the ground. A gutter that is about to fall is a hazard to anyone below.
Downpipes that crack, lean or run dry
The gutter is only half the system. A downpipe with a cracked joint, a missing clip or a leaning lower section sends water against the wall instead of to the drain. A pipe that stays dry in a downpour while the gutter above overflows is blocked inside. A pipe that bulges after a hard frost has held ice, and the plastic will not recover. Check the shoe at the bottom as well, and the gully it discharges to, because a blocked gully can back water up the pipe and make a sound gutter seem faulty. Our answer on how to unblock a downpipe explains how to clear a stoppage safely.
Winter damage and the signs it leaves
Frost is hard on gutters. Water trapped in a trough freezes, expands and pushes at joints, brackets and the channel. After a cold snap, look for joints that have opened, brackets that have bent or lifted, and splits in the front lip. A gutter that was dripping slightly in autumn and pours in spring has often been opened by ice. The damage may be local, so one hard winter is not always the end, but a run that suffers the same split two winters running is telling you something about the material.
Patchwork repairs and mismatched parts
A run built from three different shades of plastic, with a metal section spliced in and sealant smeared over a joint, is a run that has been patched many times. Each patch was reasonable, and together they show a system that keeps failing. Mismatched profiles also leak, because parts that are almost the same size do not seal. If you are on your third repair in a few years, the next spend is better put into a proper replacement.
Age and condition together
Age is a guide, not a verdict. A well-fitted plastic gutter in a sheltered position can outlast a badly fitted one by many years, and a painted iron one can last a lifetime with care. What matters is the combination: how many of the signs above you can see, how widespread they are and how far the board behind has suffered. One sign in one place is a repair. Three signs across the whole run is replacement. Our gutter maintenance guide will show you how to check before you decide.
A quick way to weigh it
Count the signs. If a gutter is basically sound and shows one local fault, such as a single leaking joint or a broken bracket, repair it. If it shows two faults that are connected, such as sagging with loose brackets, check the board, fix the fixing and reassess. If it shows several faults in different places, such as cracks, leaks and a poor fall along the run, replace it. And if the fascia is soft, treat the board first, because anything fixed to it will fail.
What happens when you leave it
Waiting is the costly choice. A leaking gutter feeds damp into brickwork and into the timber at the eaves, and the repair then grows to include fascia, soffit and rafter ends. The scaffold costs the same however small the first fault was. Our guide to gutter replacement cost shows what drives the figure, and replacing a failing run before the board goes is nearly always the cheaper course.
How we help you decide
We would sooner tell you a gutter has life in it than sell you a new one. On a survey we check each of the signs above, test the fascia behind the run, run water through the gutter to see how it behaves, and photograph what we find. The report says repair or replace, and why. Where the answer is replace, the written quote is fixed, and the work carries our ten-year guarantee on the workmanship. See our guttering, soffits and fascias page for everything we do on the roofline, or speak to the office on 01256 213956.
