Four fire engines and 25 firefighters were called to a flat fire on St Matthew Close in Uxbridge.
Half of a three roomed flat on the first floor of a house converted into flats was destroyed by fire.
The Brigade was called at 1257 and the fire was under control by 1353. Fire crews from Twickenham, Southall, Kingston fire stations were in attendance and also supported by a fire crew from Buckinghamshire fire and rescue service.
The cause of the fire is under investigation.