Four fire engines and around 20 firefighters and officers were called to a fire at a row of terraced houses in Ryefield Avenue in Uxbridge.
Part of the roof and first floor of one property was damaged by fire and part of the roof of a neighbouring property was also damaged in the blaze.
The Brigade was called at 1914 and the fire was under control at 2005. Fire crews from Hillingdon, Ruislip and Hayes fire stations attended the scene.
The cause of the fire is under investigation.