Flashing refers to pieces of metal designed to protect the junctions between the roof and chimneys, vents or dormers, as well as roof valleys and edges. These are the vulnerable areas of a roof and it is no secret that most of the leaks are caused by faulty flashing.
Flashing is most often metallic, which means that it can get corroded. The good news is that small holes can be repaired quite easily, even as a DIY project. You need sandpaper or a wire brush to clean the corroded area, roofing cement to plug pinholes, a patch made from the same material as the flashing fixed over and covered with more roofing cement.
On the other hand if the corroded area is too large and the damage too big, you will have to consider replacing the flashing. This process is more complicated and, unless you have the necessary technical skills, you should hire a roofing specialist.
As about maintenance, you should contact a Dallas roofing contractor pro to inspect the flashing and the roof shingles annually. Problems like dry or cracked roofing cement, loose nails or holes must be repaired as quickly as possible, because resealing the flashing is considerably easier than dealing with leaks and their consequences.