Six fire engines and around 40 firefighters were called to a house fire on Avon Road in Greenford.
The roof of a semi-detached house was destroyed by the blaze and part of the first floor was damaged. Part of the loft conversion and first floor of the adjoining property were also damaged. One man was taken to hospital by London Ambulance Service crews and a woman was assessed on scene.
Station Commander Graham Adams, who was at the scene, said: "Crews worked incredibly hard in hot and arduous conditions.
"Firefighters used a 32m ladder to put water on the fire from above and to monitor the blaze.
"There were some localised road closures in place so we advised motorists to avoid the area where possible."
The Brigade's 999 Control Officers took eight calls to the blaze.
The Brigade was called at 1313 and the fire was under control by 1519. Fire crews from Southall, Northolt, Hillingdon and Heston fire stations were at the scene.
The cause of the fire is under investigation.