Step flashing is a type of flashing that goes where a roof meets a sidewalk and stops water from penetrating the roof as it rolls down into the gutter. The gap between the roof and sidewalks are a very common area for leaking, especially when the flashing is re-used and has holes in it. A lot of times insurance companies do not pay for this initially, but it must always be done and they will typically pay for it when they see the holes in it from where the shingles used to lay. We ALWAYS replace step flashing when you do a roof. This is one of the first corners cut by a low bidding contractor.