Is the reason the shingles are raised at the valley due to the metal flashing being installed poorly under the shingles or is this a sheathing issue or is there another reason? Roof has one layer & was installed recently.
They also did a crappy job of sealing the flashings.
Kinda hard to see, but if you méan that bump to the left of the valley, I see it when I enlarge the picture, but can’t explain it.
When there are valleys there will be two layers of roof covering where the shingles overlap. In the picture it was difficult to determine the cause however, it appears that the flashing was not secured at the proper intervals.
ONE ANSWER!
Poor workmanship!
Is the lump on one side only? Were their any signs of past water intrusion in the attic? If not, I would probably let the clients know they should monitor that area in the future and converging roof surfaces are more prone to leaks anyway.
I would try really hard to get a close look at the intersecton of the roof with that wall, both at the exterior and interior and to get a moisture meter on both the valley and the wall intersection at the interior.
