Four fire engines and around 25 firefighters were called to a fire at a residential block of flats on Dirleton Road in Stratford.
Half of the roof of the building and part of the wooden fascia in a stairwell were damaged by fire. There were no reports of any injuries.
Sub Officer Matt Evans, who was at the scene, said: "On arrival, crews were faced with heavy, black smoke coming out of the roof of the building.
"A fire had started in a garden and spread to an open walkway which led to residential balconies.
"The roof of the stairwell was damaged by the blaze, but crews worked really quickly to stop the fire from spreading to any of the residential properties."
The Brigade was called at 0928 and the fire was under control by 1049. Fire crews from East Ham, Poplar and Plaistow fire stations attended the scene.
The cause of the fire is under investigation.