Rain water: Rain water will accumulate along the foundations or beneath the floor during rainy seasons unless directed away by proper drainage. It is very hard to control damage caused by rain water but it is possible to reduce its effects
Gutter & Drain: Clogged gutters will push rainwater under shingles, or will cause water to travel down the walls internally. A lack of drains can cause an overflow. Gutters must empty far enough away from foundation walls or else water will accumulate, leading to damage and a wet basement and even to foundation problems.
Windows and Doors: Unprofessionally installed windows and doors will allow water to penetrate into the wall. Damaged seals around windows or doors can cause windblown moisture penetration. Check your doors and windows thoroughly especially during wet seasons.
Leaking Roofs: Old roofing materials can expose the roof deck to water intrusion and damage especially around chimneys and exhaust fans. Old shingles will curl and crack, allowing moisture intrusion. Cracked chimney caps allow water into interior areas of the chimney. 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.