Roof leaks can be one of the worst surprises for a house owner; but they can be avoided by periodic inspections. If you see leaks around your chimney, or notice that your ceiling has water stains, you may need to replace the flashing on your chimney. You should reinstall chimney flashing if you notice that the existing chimney flashing is damaged or rusted. Often, replacing some shingles and re-flashing a chimney is enough to cure the problem, and much less expensive than a new roof!