Six fire engines and around 40 firefighters attended a fire on Coppermill Lane in Walthamstow.
The fire occurred at a mid-terraced house that has been converted into flats. Most of a flat with a loft conversion was damaged by fire. One man was taken to hospital by London Ambulance Service to be treated for smoke inhalation.
The Brigade received the first of seven calls at 1448 and Control Officers mobilised crews from Walthamstow, Leyton, Tottenham, Leytonstone and Homerton fire stations to the scene. The fire was brought under control by 1546.
The cause of the fire is under investigation.