At the roof's base, set a tape measure of half an inch from the roof's edge to determine how much the shingles will overhang the drip edge. First, make a mark 12 inches above the roof deck for the first course of shingles, and then make further marks every 5 inches to establish the reveal.
The property owner or the person who hired the roofing contractor can be held responsible for neglect, interference, and a lack of required documentation, even if you have no control over their conduct (and in some situations, they may be at fault). Depending on the specifics of each incident, a roofer's legal responsibility could be different.
Yes, the roofer can workduring rain. It is possible to repair or replace a roof even if it is wet outside. A building with a flat roof would be the only notable exception. Roofers must take extra precautions to ensure their safety when working in wet conditions, such as during a rainstorm.