I've had a persistent leak for two years and can't find the source. It comes in where the wall meets the ceiling. I've caulked all around, had the flashing around all the penetrations inspected, and recently had siding and gutters replaced, during which we inspected the flashing and added a better drip edge, all to no avail. My contractor tells me the roof pitch may just be too shallow for shingles to work well. He estimates it at 2/12.
I had the roof replaced in 2003 because it leaking then, which at the time I attributed to skylights that I had removed. I just found the original contract for the earlier roof replacement, and it records the pitch as 3/12 (actually it says 3/5 in 12 but I assume that is referring to a steeper part of the roof that was also involved in that project.) That contractor never told me that shingles might not be the best choice.
My questions are:
Does it sound likely to you that replacing the shingles with a material more suitable for a low-pitch roof could resolve the leak?
Do I have any case for asking the original contractor to do the work or cover the cost of another company doing it? (It has caused considerable interior damage as well.)