How to stop a leak at guttering corner joint

[bobby04]

Could anyone possibly advise how best to stop a leak where the guttering is joined at a corner (one is a right angle corner, the other is sort of 45deg corner). To further complicate this query, one of the gutters in question is pvc, the other aluminium (not mixed and matched obviously - we're talking two seperate buildings, two seperate leaks here). I thought now might be a good time of year to tackle it as I might have some chance of working on it dry. I did try silicone (? I think that's what I used) on the pvc gutter last year, but no joy. It still allows water to drip out furiously from underneath the gutter corner when it rains, and this is starting to affect the paths below the drip.

 

[DavyJones]

mother in law had same problem, using silcone is just treating the symptom I feel, although it worked for me. I had to increase fall in gutter as water sat in that corner and I make sure the gutters are cleaned atleast once a year to prevent small bolckages that prevent all the water leaving the pipe.

 

[rory22]

It is almost impossible to stop a leaking corner without opening the joint cleaning surfaces and also drying them out 100% before getting some high quality (low modulus) silicone to reset the joint. If the gutter is leaking for a long time after rain it could be pooling in the corner and as DavyJones said you may have to adjust the fall.
One thing is for sure 'buttering' silicone over the problem will not work as water has a habit of finding a way through.

Also just because water is dripping from the bottom this doesn't mean the leak is there, the water could be building up, overflowing at the back of the gutter and running down the gutter so it might be worth checking for obstructions such as a tennis ball or something like that

 

[Carpenter]

My own gutters were leaking in places after the silicone used originally had failed (after nearly 9 years service albeit). I waited until we had a relatively dry spell, cleaned out the gutters and remove the defective silicone as effectively as I could. I dry the affected areas and cleaned them with white spirit. Once this was dry I re-caulked the joints with silicone and the problem was cured. These joints aren't under pressure, so as long as the gutters are clean and dry there should be no great difficulty in sealing them with silicone. Gutters should be cleaned twice per year, it's also a good opportunity to inspect the gutters and roof for damage or potential damage.