I live in South Florida and bought my home a year ago. It has a 20 year old concrete tile roof that is very nice. I have been getting a tiny leak on the patio roof where it ajoins the main roof. It has a flat non tiled surface.
On closer inspection I notice the entire roof surface including the tile has been coated with some type of acrylic sealer. It's a white felxible material. The sealer has some age/heat related cracking on the flat patio roof and I belive durning heavy rains water is making it's way through these cracks in the coating.