Four fire engines and around 25 firefighters were called to a house fire on Roxeth Grove in Harrow.
Half of the first floor and loft in a semi-detached house were damaged by the fire. One man was treated for smoke inhalation at the scene.
The Brigade was called at 1237 and the fire was under control by 1400. Fire crews from Northolt, Wembley, Harrow and Stanmore fire stations were at the scene.
The cause of the fire is under investigation.