Four fire engines and 21 firefighters and officers were called to a fire at a house in Ballogie Avenue, Neasden.
Most of the first floor was damaged by fire. A small part of the roof and the first floor of a neighbouring property were also damaged in the blaze.
The Brigade was called at 1047 and the fire was under control at 1140. Fire crews from Finchley, Willesden, and Wembley attended the scene.
The cause of the fire is under investigation.