Extra firefighters were needed to help with a duplex fire Saturday in Janesville because of this weekend’s heat and humidity. The duplex was located in the 300 block of North Chatham Street, said Janesville Fire Department Battalion Chief Ron Bomkamp. Firefighters arrived to find smoke coming from the roof of the building. Extra firefighters from Janesville and the Footville Fire Department were called in to help because of the heat, Bomkamp said. The Red Cross is helping the six adults and two children displaced by the fire.