Most people do not realize it is important to perform periodic maintenance in order to keep your Tile Roofing System watertight. Built-up debris in the Valley areas of your roof can cause water to back-up and not drain properly potentially causing expensive interior water damage. Be sure to sweep or blow out these areas periodically especially if you have trees adjacent to your home.  Also, keep trees and tall shrubs trimmed back to lessen the chance of rodents entering your attic space from the roof.