Four fire engines and around 25 firefighters were called to a fire at a shop with flats above on High Road in Tottenham.
Half of the loft and part of the roof of the building were damaged by fire. Around 10 people left the building before the Brigade arrived. There were no reports of any injuries.
A London Fire Brigade spokesperson said: “Smoke alarms fitted inside the property alerted residents to the fire in the common roof space of the building.
“Smoke alarms give the earliest possible warning to fire, providing time to escape. You should have smoke alarms in every room where a fire could start, plus a heat alarm in the kitchen. It's important to test them regularly."
The Brigade was called at 0611 and the fire was under control by 0656. Fire crews from Tottenham, Edmonton, Stoke Newington and Walthamstow fire stations attended the scene.
The cause of the fire has been recorded as undetermined.