Metal flashing prevents leaks where shingles meet other surfaces, like walls and chimneys. Proper flashing work takes time and know-how, so sloppy roofers sometimes slather on roof cement instead. It seals out water long enough for them to cash your check, but it soon hardens, cracks and leaks. In the end, all it does is make a proper repair more difficult. So if you see heavy 'tar' patchwork on your roof, fix it right—before it leaks and leads to interior damage.
No Chimney Cricket
Missing Kick-Out Flashing
Kick-out flashing is critical where a roof edge meets a sidewall. Without it, roof runoff flows down the wall and possibly into the wall. This is worst when there is a door or a window below and water can seep behind the trim. You might not notice it for years, but eventually rot will destroy sheathing and framing. In extreme cases, the stucco is the only thing holding up the wall! Don't wait for that to happen to you. To see how to add kick-out flashing, read Use a Kick-Out Flashing to Stop Rot.