Does anyone have an idea why this happens? We had a new asphalt shingle
roof put on about 5 years ago. The chimney lead flashing was replaced
with new, and when all done, it was lying flat on the shingles as it
About 4 months ago I noticed that one of the corners of the lead had
curled up enough that wind-driven water might have been able to get into
the house, so I went up on a step ladder and reached up with a very long
snow roof rake to squash it back down flat. Worked easily. Now, i see
that it is slightly curled up again, lifted perhaps an inch at this point.
Does anyone know what the mechanism is that is causing the lead flashing
to curl up on that one corner?