Roof valley leak

7 Dec 2018
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United Kingdom
I have a grp valley fitted and I'm getting water behind facia board at bottom valley. The things I can see that are wrong are valley kicks up at bottom and battens push into membrane causing it droop. Also roofer has not done v cut into gutter of valley and has left straight, hence side channels of valley end on top of fascia. Also tiles on both sides of valley at eaves also kick up too much. I was thinking of cutting fascia boards down by say 15mm for example so tiles on both sides valley slope more and also putting v cut in fascia for valley to sit Lower,also put newn1m piece valley in at bottom. Any thoughts guidance?
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Change the bottom of the valley from grp to lead sheet so it dresses down and sits better.
without seeing it, you might try slipping a piece of lead 450 x 450 mm up under the grp but turn the edges up and back on their selves
notching the fascia and lengthening the grp is an option too
So if I use the lead do I need to still notch fascia. Also valley battens are pushing felt down so that it pools and does not slope down nicely over fascia under bottom of valley.
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Will try taking a picture of it tomorrow and posting. Also I think because the tiles either side are kicking up at eaves that water may be getting in there. Especially the tile on the right side found wet under there and it didn't seem to be tracking down from under tiles above.
Hope these pics are decent enough. Please take a look and any guidance appreciated.


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That's a bizarre valley moulding - whats the ridge down the middle ? Is it a valley gutter fitted upside down or even a bonding gutter for 2 roofs ? Just google glass fibre valley gutter and see what I mean.
The Grp is one of the many makes out there..
Notching the fascia is what we tend to do - If you don't want to do this then as said , trim the GRP back a bit slip a decent size piece of lead up under the GRP and turn the edges up
Can you zoom into the very top of the valley. I think you are getting water from higher up too.
At least one tile on the RH side has a channel damaged and needs replacing (Marley Modern)

And after all that , your roof has a fair bit of sprocket (kick) governed by the height that the fascia has been set. Not strictly correct but not the end of the world...
Thanks datarebal. The tile with the lead on is a temp repair. Will replace this tile. Is this the damaged tile you are talking about? I think I would need to drop fascia on right side by 2.5cm so pitch of eaves tiles matches those above. The fascia on left side would only need to drop by 1cm. What do you think about doing this. Would 1inch notch in fascia for valley be okay.
No not that tile there is another . The course above that one , second tile in is damaged.
25 mm each side would be ok provided the gutter corner allows it.
Check the top of the valley
Checked that tile already although some damage it is covered by tiles underneath it. Are you talking about tiles at top of valley as think they are ok or the saddle, I can take more pics if that helps.
that tile is damaged...85p worth changing..
yes the saddle doesn't look quite right
Roofer did take look up valley never mentioned about saddle. What do you think doesn't look right.
In addition couldn't understand why felt under tile on right of valley at bottom was wet.

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