Traditional sand-and-cement bedding used along the peaks of your roof is completely rigid. As the sun heats your roof up during the day and cools it down at night, the structural timber framework underneath expands and contracts. Because old cement cannot flex, it fractures, breaks apart, and blows away, leaving the ridge caps loose and exposed to leaks.

No, thick roof coatings or paints are strictly aesthetic and will not fix an active leak. Water entry points are structural—such as rusted valley irons, cracked flashing collars around ventilation pipes, or displaced tile lugs. Spraying paint over these faults merely hides the problem temporarily while the structural timber underneath continues to rot.