Four fire engines and around 25 firefighters were called to a fire at a house converted into flats on Cranley Gardens in Hornsey.
A first floor flat was destroyed by the fire and part of the first floor flat roof and part of a ground floor flat were also damaged. One man was taken to hospital by London Ambulance Service crews.
The Brigade was called at 0930 and the fire was under control by 1111. Fire crews from Hornsey and Finchley fire stations were at the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.