Ceiling stains or actual water leaks are signs of condensation in the attic or water getting through the shingle covering. While stains may appear negligible, they are likely the advance warning of future roof problems and costly interior repairs.
On the roof
Is your roof more than 10 years old? If it is, any of the following signs of weathering or damage are an indication that your roof may need help.
Aging
1) Bare spots - areas in which the protective granular surface has worn off.
2) Accumulation of granules in the gutters.
3) Fine fissures in the shingle surface which widen through weathering.
Broken or missing shingles
Damage can be caused by extreme wind conditions and snow removal. This may take the form of broken, torn or missing shingles which can permit the entry of water.
Buckling
Caused by warping of roof decks, buckling is a visible distortion of the horizontal lines od shingles on the roof, going up the roof slope. Shingle tabs become exposed to wind and can be torn off, again permitting the entry of water.
Clawing
Curling under of the shingle tab's bottom edge. The bulge created is susceptible to substantial damage be wind action, hail or ice.
Curling
An upward curling of shingle tabs, making them highly susceptible to wind and ice damage.