Resources
What causes roof leaks?
Flashing, penetrations, aging shingles and drainage — the usual paths water uses.
Most leaks are details
Water often enters at chimneys, walls, valleys, vents and skylights — not in the middle of a perfect field. Failed flashing and unsealed penetrations are everyday findings.
Field wear still matters
Missing shingles, cracked pipes boots and worn underlayment can wet the deck away from a chimney. Age plus weather opens more than one path.
Drainage
Overflowing gutters and ice or debris at the eave can push water under the covering. The leak may present inside while the opening is at the edge.