Visible, Preventable Causes of Water Damage
Roofing materials wear out and expose the roof decking to moisture intrusion and damage. You need to periodically inspect roof penetrations such as chimneys, plumbing vents, and exhaust fans. Watch out for worn shingles which curl and crack, allowing moisture to seep underneath. Cracked chimney caps allow water into interior areas of the chimney. Rain water which accumulates between the roof and blocked gutters can be a source of considerable damage. The rain water will back-up under the shingles and weaken the decking. Keep your gutters as clear as possible, especially during the autumn months when the leaves turn and fall. Flat roof drains can clog and hold water on the roof, increasing the risks of a leak and a possible collapse of the entire roof under the weight of the water or snow.
Poor attic insulation and ventilation allow heat to escape, turning rooftop snow into an ice dam. Ice dams can force moisture to back up under roof shingles where it can drip unseen into the attic or walls.
Improperly installed windows and doors allow moisture to penetrate into the walls. Damaged seals, weather-stripping, and flashing around windows or doors can cause windblown moisture penetration.
Gutters & Drains
Clogged gutters can force rainwater to travel under shingles, or to overflow and travel down interior walls. An insufficient number of drains can cause an overflow. Gutters that don't empty far enough away from foundation walls can lead to damage and a wet basement. Frozen gutters can act like ice dams, pushing moisture up under the shingles and into the house.
Rainwater collects along the foundation wall or beneath the floor during wet months unless directed away by proper drainage.
Improper landscape grading can result in drainage toward foundation walls, rather than away from them.