Damp patch on the external wall under the roof lining.

[TalktoDavid]

Good Afternoon,
I wonder if someone in the know can kindly give me an idea of what might be causing this issue. The valley above the wall has been redone, the internal walls are completely dry, the loft has no water ingress around this area and there is no gutter leakage. The damp "pattern" seems to be consistent, missing some bricks but darkening others. It doesn't cause a problem but looks bad from the front of the house. Thank you.

 

[noseall]

Good Afternoon,
I wonder if someone in the know can kindly give me an idea of what might be causing this issue. The valley above the wall has been redone, the internal walls are completely dry, the loft has no water ingress around this area and there is no gutter leakage. The damp "pattern" seems to be consistent, missing some bricks but darkening others. It doesn't cause a problem but looks bad from the front of the house. Thank you.View attachment 371677

Broken or missing tiles

 

[TalktoDavid]

Thanks for your reply. No tiles broken or missing. Roof appears to be in good condition with no issues visible, using binoculars.

 

[noseall]

Thanks for your reply. No tiles broken or missing. Roof appears to be in good condition with no issues visible, using binoculars.

The only other thing I can think of is the valley discharge into the gutter is faulty somehow. It maybe blocked or restricted by the valley soaker, or its overwhelmed or the water is tracking back..?

 

[TalktoDavid]

Thanks - yes that's passed me by and is certainly worth looking at. A long ladder and watch what happens in a downpour!

 

[ree]

OP,
What do you mean by "the valley has been redone"? Why was it redone?
If you open the top window light, & use a long batten as a selfie stick you will be able to pic the valley & the gutters. No need to wait for rain.
Your house was possibly built with fibre glass or rockwool batts cavity insulation - damp could eventually penetrate the brickwork & perhaps soak the CWI & the inside skin?
A weep is visible and appears to be in use.
The lead apron FWIW should have been returned at the abutment.

 

[TalktoDavid]

Thanks for your reply. I'm ashamed to say....! I had some roof work done about 12 years ago (ridge ties blown off) and the scoundrels that did the work ripped the valley apart, telling me it was in need of refurb. They wrecked it and did little to put it right. I had to call in reputable firm who completely replaced it. It is fine now. TBH I have waved my iPhone out of the window on a stick but it's not that easy to get a clear picture. .
I'm afraid your last two points are alien to my skill set.... I wonder if you can clarify for this amateur please? Thanks.