Six fire engines and around 40 firefighters were called to a house fire on Station Road in Hendon on 24 May.
Half of a flat in the mansard roof of a mid-terraced house was damaged by fire. Five people left the property before firefighters arrived and were taken to hospital by London Ambulance Service to be treated for smoke inhalation.
The Brigade's Control Officers received around seven calls about the fire.
The first call was received at 0754 and Control Officers mobilised crews from West Hampstead, Finchley, Stanmore and surrounding fire stations to the scene. A 32-metre turntable ladder from Paddington Fire Station also attended and was deployed as a water tower to help extinguish the fire from above. The fire was brought under control by 0900.
The cause of the fire is under investigation.