Roof Valley Leaking. Felt under valley in loft very wet and wet joists in loft after rain. Possible issues?

[MalcolmReeve]

Last year, I discovered that the felt in my loft under a valley was very wet after a lot of rain. I was thinking that the rain was getting through the morter, so I got the valley repointed. However, the issue remains. My roofer has checked for any cracked tiles near the valley - none and he says that the lead in the valley is in good condition. I'm stumped. If rain is not getting through the morter, there's no cracked tiles and the lead is in good condition - what else could it be?

 

[DAZB]

It may be a hairline crack on a tile or ridge that is hard to spot or could be running down the underfelt so may be entering nowhere near the point of visible ingress. May be worth having a look in there during heavy rain to see if you can spot anything.

 

[MalcolmReeve]

Thanks, DAZB. I had a new dry ridge installed last year. The wet patches on the felt start half-way down the valley.

 

[datarebal]

have you a valley picture?