Hi,

I have a problem with an angled roof valley. It has concrete gully tiles
which leak at the joints resulting in the felt rotting under the joints.
This has been mainly caused by strong south-westerly winds which tend to
"funnel" straight up the valley.
I intend to lead the valley over gravel boards and have a pamphlet
(Lead Association) but it does not show precisely the position of
the felt. At present I have a (damaged) felt running down the valley
with the normal felts on top of it.
Can someone give advice on the correct/best method:

1. Do the felts go under the whole valley (with
boards and lead on top?
2. Do the felts go between the lead and boards?
3. Do the felts go just up to the gravel boards with the lead overlapping
it by, say 80 mm?
I have also been advised to lay an extra triangular piece of board
along the length of the valley to give it a flat bottom rather than leave
it as a "V" shape. Any comments welcome.

Thanks