Rooftop Patio in Paradise!?...any advice?

A constant, never-ending battle for us over these many years. We chose form over function and tiled ours. Have since sealed, resealed, retiled with several different sealers, both sub-tile and on-tile. We get it stopped for a while then along comes an earthquake (or just time passes) and a new leak appears. We have decided it's part of the price we pay for living in this otherwise marvelous house in this wonderful part of the world. Solo es la vida, creo.