Make Sure the Flashing is Intact – The flashing is a metal lining that is installed into roof joints to seal breaks in a roofline and prevent leaks from occurring. Most roofs have flashing around vents and chimneys. If installed correctly the flashing make use of gravity to send any water off the roof and to the ground. In can be hard for the layman to actually tell if their flashing is in good shape or not, so it may best to have a professional roofer take a look, especially if you have an older roof.
Eliminate Rooftop Debris – Since your roof obviously sits exposed at the top of your house it is bound to accumulate a good amount of debris over time. Excessive amounts of leaves can lead to water pooling especially in the winter, making a roof leak more likely. Moss can also be a real problem and if not dealt with can eat away at the roof and compromise its structure. Have a roofing contractor power wash or otherwise clean up your roof at least once or twice a year.
Clean the Gutters – Gutters clogged with leaves and other natural debris can cause a real problem if left unchecked. A clogged gutter can lead to water backing up and staying there – leading to leaks. If you cannot reach the gutters to clean them efficiently yourself, hire someone to do it for you, it is well worth the extra expense.
Even with all your prevention efforts if your roof does seem to have sprung a leak get it professional help as soon as possible! The longer a roof leak is allowed to continue the worse the damage is likely to be, so do not delay calling in a professional roofing contractor.