Four fire engines and around 25 firefighters were called to a fire at a bungalow on Benhilton Gardens in Sutton.
Most of the roof and part of the ground floor of the three-bedroom detached bungalow were destroyed. There were no reports of any injuries.
The Brigade was called at 1300 and the fire was under control by 1431. Fire crews from Sutton and Tooting fire stations attended the scene along with colleagues from Surrey Fire and Rescue Service.
The cause of the fire is believed to be accidental.