Four fire engines and around 25 firefighters were called to a fire at a row of shops with flats above on Wood Street in Walthamstow.
Half of a mansard roof and part of a first floor flat were destroyed by fire. Crews wearing breathing apparatus extinguished the fire. No injuries are reported.
The Brigade's 999 Control officers received eight calls alerting them to the fire. They deployed fire crews from Walthamstow, Leyton, Woodford and Leytonstone fire stations.
The cause of the fire is believed to be accidental and most likely due to hot works being carried out on an adjacent part of the mansard roof.