Four fire engines and around 25 firefighters were called to a fire at a shop with maisonettes above on Clapton Common in Hackney.
A five-roomed maisonette on the first and second floor was damaged by the fire. There were no reports of any injuries.
The Brigade was called at 0526 and the fire was under control by 0721. Fire crews from Stoke Newington and Tottenham fire stations were at the scene.
The Brigade's Fire Investigators believe the fire was accidental and caused by building works which were being carried out.