Four fire engines and around 25 firefighters tackled a fire at a semi-detached house on Dunheved Road South in Thornton Heath.
A loft extension was destroyed and half of the first floor and most of the roof were damaged by the fire. Ten people left the building before the Brigade arrived. There are no reports of any injuries.
Control Officers took the first of two calls at 1813 and mobilised crews from Norbury and Croydon fire stations to the scene. The fire was extinguished by 2009.
The cause of the fire is under investigation.