The roof guttering (plastic ,black, fitted when the roof was done 7 years
ago) leaks from the join. It is a proper, but narrow joining fitting/clip I
cleaned it once without success and last year gunged it with unibond roof
and gutter sealant, which for reasons I don't understand made it worse.
I need to have another go. I bought a wider fitting clip, but I'm not sure
whether I can get to the screws under the slates and since I will be two
floors up on a ladder I need to think ahead a bit. The other option seemed
to be to clean the gunk off the trough and use flashband. There is
expansion I suppose, but the total length is 4 m high side and 3 m low
side, although I also suspect that the run is not straight and water
collects at the join a little.
Will I be able to get the gunge off, if so how?

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Jim S
Tyneside UK
www.jimscott.co.uk