Six fire engines and around 40 firefighters were called to a fire at a derelict house on Newlands Park in Sydenham.
The roof, first and second floors of the building were destroyed by fire and most of the ground floor was also damaged by the blaze. Firefighters removed one gas cylinder from scaffolding on the building at roof level and cooled it to an ambient temperature as some cylinders can explode when exposed to heat. There were no reports of any injuries.
Station Commander Danny Slay, who was at the scene, said: "This was a particularly visible fire at a semi-detached house that had been derelict for a number of years.
"Crews worked incredibly hard to gain access and bring the fire under control. They remained on scene throughout the night damping down remaining hot spots."
The Brigade was called at 1616 and the fire was under control by 1955. Fire crews from Forest Hill, Lewisham, Croydon, Bromley, Beckenham and surrounding fire stations attended the scene.
The cause of the fire is under investigation.