Four fire engines and around 25 firefighters tackled a fire at a shop with flats above on Porters Avenue in Dagenham.
Half of the second floor of the building and part of the loft were damaged by fire. There were no reports of any injuries.
The Brigade's Control Officers took the first of 13 calls to the fire at 2145 and sent crews from Barking, Dagenham, Greenwich and Plaistow fire stations to the scene. The fire was under control by 2251.
The fire is believed to have been accidental and caused by an electrical event.