Four fire engines and around 25 firefighters were called to a fire at a bungalow on Nether Street in Finchley.
Part of the ground floor and half of the roof of a derelict, detached bungalow was damaged by fire. There were no reports of any injuries.
The Brigade's 999 Control Officers took 12 calls to the fire.
The Brigade was called at 1746 and the fire was under control by 1837. Fire crews from Finchley, Mill Hill, Barnet and West Hampstead fire stations attended the scene.
The cause of the fire is under investigation.