Six fire engines and around 40 firefighters were called to a house fire on Kyrle Road in Clapham.
Most of the loft conversion of a mid-terraced house was damaged by fire. Two adults and four children left the building before the Brigade arrived. There were no reports of any injuries.
The Brigade was called at 1937 and the fire was under control by 2149. Fire crews from Battersea, Tooting, Clapham and Wandsworth fire stations attended the scene.
The fire is believed to have been caused by combustible items too close to a heat source.