Industrial Roofing Tips
If you have a Tar and Gravel Roof check to make sure the Gravel is not disturbed. The tar underneath the gravel will deteriorate quickly if it is exposed to the elements, especially the sun.
It is also critical to watch for Tree branches which might rub against the roof and erode the roof membrane, and eventually cause a leak.
Hanging Christmas lights can be risky for roof leaks as well. People don't realize that using even staples (or nails, or hooks) can cause holes on the bottom edge of the roof.
If there are sharp objects on the roof and someone walks on the roof and steps on the sharp object, this can puncture the roof membrane.