Gutter Leak - Fixed...Leaking again...Fixed....Leaking again

1 Jun 2010
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United Kingdom
Hi everyone, im new here but am tearing my hair out. I've skimmed the forum for advice but nothing seems to match the problems im having.

Basically, my upvc guttering started leaking at one of the joins. I first tried to fix it by running gutter sealant over the join. This failed and the next time it rained the leak was just as bad. It was suggested that due to all the expanding and contracting with the hot and cold weather, maybe the gutter had moved and was therefore not making a good seal with the join. Next time it rained and the water was pouring out, i went up and pulled the gutter along slightly (more of the gutter on the join). This instantly stopped the leak. However, a few days passed of sunshine and then cold again, followed by more rain and once again, a leaking gutter. This suggests to me that the gutter has again moved due the weather.

Does anyone have any suggestions on how to best proceed? Im at the point of calling in the experts but fear their fix could be as short lived as mine. i.e. fixed at the time but leaking again in a weeks time.

Any help would be much appreciated.

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If the leak is at a join where 2 lengths of gutter meet up just go and buy a new joiner?

Its called the union, Unclip your old one re-clip in the new one should be no more than a few quid.

Gutter sealent is only really a short term fix IMO, What tends to perish is the rubber seals that come with the Union join.
Zeberdee suggestion is the best way to fix although you can fix with silicone and be effective=remove the union(jointer) dry this and the gutter,apply your silicone then clip back together.As long as its clean and dry and done this way willl be effective and last many many years(Use silicone not mastic).If replacing union Make sure the union you get is the same as what comes off as there are different styles/sizes some look the same but slightly different size/shape,best to take your old one with you when buying a new one.Also inside each union(jointer) there are 2 markers where your gutter goes so you have the correct amount of over lap. ;)
Thanks both. Im hesitant to replace the union in case i cant get an exact match and make matters worse with a new one. Zeberdee, It looks like i might have to if the final attempt to repair (using sealant) doesnt work.

Cumbrian, when you say use silicone not mastic, I have unibond roof and gutter sealant, is this any good? Also, you mentioned about the marking in the union. I have a feeling that the gutter is way off that mark which im guessing will not be helping the problem. I will check the other end of the gutter to see what overlap is on the downspout. If it is over the mark that end, is it ok to move the gutter across a bit further to give a better overlap on the union?

The more i read on here, the more im learning that the gutters on my estate where just thrown up. There are leaks all over the estate!
Thanks again.
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The more i read on here, the more im learning that the gutters on my estate where just thrown up. There are leaks all over the estate!
Thanks again.
done by roofers not plumbers then ;) Are they Marley :?: with a slot cut on the end of the gutter . How old roughly is the estate ?. Osma 1974 grey on a cottage in the village where I used to live . My first "big" job on my own - still perfect :LOL:
No idea what the type is Nige, all i can tell you from ground level is they semi circular, brown upvc. Not much help i bet! :rolleyes: My house is only 4.5 years old!
@dboardman Defo use silicone.Plastic gutters move ALOT with heat,you know that cracking noise you hear on a summers night coming from you eaves?thats the gutters contracting back to their original size after expanding with the heat of the day.The sealent you have goes hard in no time at all,once this happens as soon as your gutters expand the seal will be broken and you will be back at square one,silicone is very flxible,rubber like,Done the way i said it will last many many years.As for the marks on the inside of your union=yes make sure the gutter is fitted to the mark otherwise when it expands it will just come apart which seems whats happening already.Make sure you remove union,clean,dry,make sure marks in correct place,put plenty of silicone ijn(lots,you cant put too much in) so when clipped it it comes out of edges,remove excess silicone with cloth/rag and your sorted. ;)
Thanks again cumbrian. I'll go up at the weekend and line it up to the mark. What is the bet that when i go up and check the other end of the gutter, that too is not pushed up to the mark, meaning the guttering is about 10mm too short!

One last question before i hopefullt return to report my success. The silicon, is an all purpose silicon ok to use? i.e.

or would you recommend another type?

Thanks again in advance
Just use bog standard clear silicone.The stuff you mentioned is way overpriced.Try your local upvc supplier or failing that builders merchant.I pay £2 for mine,you should be able to pick it up no more than £3. ;)
Thanks for all your help Cumbrian, fingers crossed! As you can probably tell, guttering and roofing isnt my area of expertise. I work in IT so if you ever need any advice on anything computer related, give me a shout, it's the least i can do.


You need to stop the gutter creeping due to the thermal expansion and contraction. I would suggest that you remove a couple or so gutter brackets - one at a time will do - save having to worry about holding up the gutter. Find yourself some long non-ferrous screws (to avoid rusting) and refix the gutter brackets but this time use the longer screws to fix through the gutter and the gutter bracket so that the gutter is directly screwed to the facia board.

you can not stop thermal movement, it will simply buckle up elsewhere.
get the gutter fitted properly.

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