“Compensable time”

Ron and Tim both work as landscapers during the summer months. Due to the heat, the scheduled start time is 7 am. Typically though, the crew leader is late, and most days they do not start work until 7:30 or 8 am. Ron likes to catch a quick nap while he waits. However, Tim usually will pick up a broom or clean to pass the time. What time would his “compensable time” begin for Ron and Tim (assume that 7:45 is the average start time)?