Six fire engines and 35 firefighters and officers were called to a fire at a semi-detached house conversion in Chase Side, Enfield.
Half of a loft and part of the first floor flat was damaged by fire.
The cause of the fire is believed to be an electrical fault.
The Brigade was called at 1122 and the fire was under control at 1342. Fire crews from Enfield, Islington, Edmonton, Southgate, and Chingford fire stations attended the scene.