Four fire engines and around 25 firefighters tackled a fire at a mid terraced house on Montacute Road in Morden.
Half of the loft space was damaged by the fire. There were no reports of any injuries.
The fire is believed to have been accidental and was caused by combustible items left too close to a heat source.
The Brigade was called at 1556 and Control Officers mobilised crews from Mitcham, Sutton, New Malden and Norbury fire stations to the scene. The fire was extinguished by 1657.