Four fire engines and around 25 firefighters attended a fire on Whitehall Road in Uxbridge.
Half of a first-floor flat, situated within a three-storey residential block, was damaged by fire. One man was led to safety from a first-floor pitched roof by firefighters and left in the care of the London Ambulance Service.
The Brigade was called at 2025 and Control Officers mobilised crews from Hayes, Ruislip, Heathrow and Hillingdon fire stations to the scene. The fire was extinguished by 2102.
The cause of the fire is under investigation by the Brigade and Metropolitan Police.