Question answered
Leaking gutter joint: repair or replace?
The short answer
A leaking gutter joint can be repaired if the union and the gutter either side are sound: clean, dry and reseal it, and check the fall and brackets. Replace the length, or the run, if the plastic is brittle, the metal is corroded, the brackets are loose or the joint keeps reopening. We find which it is before we quote.
A dripping gutter joint is the commonest gutter fault. Sometimes a fresh seal cures it for a while; sometimes it is the first sign that the whole run has had its day.
How a gutter joint is meant to work
Sectional gutters are joined with a union bracket. The two gutter ends slot into a clip, and a rubber gasket or a bead of sealant closes the gap. The gutter is not glued rigid. It has to move slightly as the temperature changes, so the seal must stay flexible.
When it works, the joint is barely noticeable, and nobody looks at it from one year to the next. When the gasket hardens, shrinks or slips, water finds the gap. It drips from the underside of the joint during rain, often on the same spot of the path or wall each time, and leaves a green or black trail below.
Cast iron and older metal gutters are bolted at the joints with a putty or mastic seal between the faces. That seal dries and cracks with age. A joint that has been dripping for years has often rusted at the bolts as well, which makes a simple reseal unreliable.
Why joints fail
The usual reason is age: the gasket loses its spring, or the sealant cracks. Next comes movement. If the brackets near the joint have loosened or the fascia behind has gone soft, the joint is pulled apart a little more with every storm, and no seal will keep it shut.
Debris and a poor fall play a part, too. A gutter that holds standing water puts constant load on the seal, and any dirt in the joint stops it closing properly. Sun and frost add the final stress, and uPVC in particular becomes brittle as it ages.
On site, the first thing we check is the condition of the clips and screws, because a fixing that has weakened lets the joint creep open.
When resealing is enough
A reseal makes sense if the gutter and union are firm, the plastic or metal is clean and not cracked, the brackets are tight and the fall is right. The fitter dries the area, cleans out the old sealant, refits or replaces the gasket and applies the correct sealant for the material.
Do not smear silicone over a wet, dirty joint. It may stop the drip for a few weeks, but it lifts at the first frost and hides the cause. A repair that works starts with a dry surface and a joint that is free to sit square, with the gutter either side supported close to the union so it cannot flex.
If you want to have a go yourself from a safe position, you can check how the joint sits from a stable ladder with someone footing it, or leave it to us. Either way, dry weather is the time to work. For a general look at maintenance, see salt air and the roofline for what the coast does to fittings over the years.
When to replace the length or the run
Replace a length if it is cracked, split along the seam, corroded through or has lost its shape so the union no longer closes, because no sealant can bridge a gap in a distorted section. Replace the run if several joints leak, the plastic snaps when touched or the gutter has stretched between brackets. A tired system rarely fails at just one point, and patching joint after joint can cost more over a few winters than renewing the run once.
MyBuilder gives a typical UK range of £30 to £70 per metre for gutter replacement (updated 21/08/2026). The final figure depends on access, run length and eaves height, and the written quote, a single total, follows the survey.
A run with fewer joints, such as seamless aluminium gutters, reduces the number of places for this fault to start, but only if the fall and brackets are right. Gutters that have already damaged the board need that put right first.
What a leaking joint can do if it is left
A drip looks minor, but it falls on the same spot of wall, fascia or soffit for months. The board behind goes soft, brickwork stays wet and may stain or grow algae, and damp can move through to the inside of the wall. If the joint sits above a door or window, the drip can land on the frame.
If a storm has opened the joint, your policy may or may not respond. Read the points in gutter damage and insurance before arranging permanent work. Policies often carve out damage that builds up slowly, according to the Financial Ombudsman Service, and a long-running drip may fall into that category.
Our gutters, soffits and fascias page lists the other repairs we carry out along the eaves. If the board is already marked, look at the signs a fascia needs replacing, and at the gap behind the gutter described in the gap between the roof and the gutter.
Dripping joints: two things to check
Is silicone a proper repair for a gutter joint?
Only as a short-term measure on a clean, dry joint. It will not hold a loose union, a cracked length or a bad fall. We reseal with the right gasket and sealant where the parts are sound, and replace the length where they are not.
Why does the joint leak only in heavy rain?
Because heavy rain fills the gutter higher, so water reaches the top of the seal where a small gap sits. It can also mean the outlet is blocked and the run is holding water. Clearing the gutter and checking the fall tells you whether the joint is the real fault.
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.