Part of the basement was damaged by fire. Three people left the building before the Brigade arrived and 10 people were evacuated from surrounding properties. One person was treated on scene.
The fire was discovered by a member of the public who could smell burning.
The Brigade was called at just after midnight and the fire was under control by 2.16am. Fire crews from East Ham, Stratford, Plaistow and Ilford fire stations attended the scene.
The fire is believed to have been caused by an electrical fault in a consumer unit located in a utility cupboard in the basement.