Six fire engines and around 40 firefighters tackled a flat fire on Winchester Road in Chingford.
Most of a three-roomed flat on the ground floor of the building was damaged by fire. There were no reports of any injuries.
The Brigade was called at 2051 and the fire was under control by 2153. Fire crews from Walthamstow, Woodford, Leyton, Leytonstone and Tottenham fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.