Four fire engines and around 25 firefighters responded to a fire on Lancaster Road Northolt.
Part of the ground floor, first floor and roof fascia of a semi-detached house were damaged by the fire. Two people left the property before crews arrived, with one treated on scene by paramedics.
The Brigade was first called about the incident at 1802, and crews from Northolt, Wembley and harrow fire stations attended the scene. Firefighters had the incident under control by 1913.
The cause of the fire is believed to have been accidental.