Four fire engines and around 25 firefighters were called to a fire on Beauchamp Road in Upper Norwood.
Most of a loft conversion within a terraced house was damaged by the fire. Firefighters rescued one man from the roof of the property via a ladder. He was treated at the scene and taken to hospital suffering smoke inhalation by London Ambulance Service crews.
The Brigade was called at 1500 and the fire was under control by 1606. Fire crews from Norbury, West Norwood and Woodside fire stations were at the scene.
The cause of the fire is under investigation.