Barry talks to Iris as The Flash on the roof in episode 1x05 "Plastique". From episode 1x06 "The Flash Is Born". From episode 1x08 "Flash vs. Arrow". Appears in 3 more episodes.
Cisco stops on the rooftop Iris predicts Peek-a-Boo will stop at and uses his power to bring her down in episode 4x01 "The Flash Reborn".