Six fire engines and about 40 firefighters attended a fire at a semi-detached house over two floors on Headcorn Place in Thornton Heath.
The entire ground floor area of the house and part of the first floor was destroyed by the fire.
One woman left the property before the Brigade arrived and was attended to for the effects of smoke inhalation at the scene by London Ambulance crews.
Crews worked quickly to contain the blaze and to prevent it from spreading into adjacent properties.
The Brigade was called at 1705 and the fire was under control by 1927. Fire crews from Croydon, West Norwood, Woodside and Mitcham fire stations attended the scene.
The fire is under investigation by the Brigade and the Metropolitan Police Service.