Four fire engines and around 25 firefighters were called to a maisonette fire on London Road in Hounslow.
Half of the maisonette was damaged by the blaze. Part of the ground floor at the rear of the property was also affected.
Two men left the property before the Brigade arrived.
The Brigade was called at 1129 and the fire was under control by 1256. Fire crews from Heston, Southall and Fulham fire stations were at the scene. The cause of the fire is under investigation.