Six fire engines and around 40 firefighters were called to a fire at a maisonette on Marlborough Gardens in Whetstone.
The roof of the semi-detached building was destroyed by the blaze. One woman left the property before the Brigade arrived. There were no reports of any injuries.
The Brigade was called at 0327 and the fire was under control by 0506. Fire crews from Southgate, Barnet, Finchley and Hornsey fire stations attended the incident.
The cause of the fire is under investigation.