There are different signs of damage for different roofs. Here are some of them:
Cedar or shake roof:
A cedar or shake roof needs repair or replacement if you can see the wood splitting, algae streaks, and mounds of moss. Additionally, termite damage, missing shakes, curling, and rotting are all signs your roof needs help.
Broken or cracked tiles or missing tiles. Don’t walk on a tile roof to investigate problems you can see from the ground, hire a professional to give you a free estimate.
Granule loss – where your shingles have lost parts of the granules making up the shingle itself. Again, algae streaks or missing shingles . Blistering, buckling, rotting or curling of the shingles.
Rusted or water damaged screws or joints. Gaps between screws and joints in your roof, dents and cracks in your roof.
If you suspect your roof is damaged, even if it’s not leaking yet, get a professional roofer to come take a look at it.