Eight fire engines and around 60 firefighters were called to a house fire on Central Avenue in Hounslow.
The roofs of two terraced houses were destroyed by fire and part of the first floors were damaged by the blaze. Part of the roof of another adjacent house was also damaged by fire. There were no reports of any injuries.
The alarm was raised when members of the public saw smoke coming from the chimney and called 999. Five adults and four children then left the properties before the Brigade arrived.
Station Commander Glen Nicolaides, who was at the scene, said: "The fire was located in the roof of one house and spread into the roofs of two adjacent houses. Crews worked to remove tiles to gain access and bring the fire under control.
"There was very heavy smoke in the area and local residents were advised to keep their windows and doors closed.
"People were encouraged to avoid roads in the surrounding area due to road closures which were in place throughout the evening."
The Brigade was called at 1547 and the fire was under control by 1909. Fire crews from Heston, Feltham, Hillingdon and surrounding fire stations attended the scene.
The Brigade's Fire Investigators believe the fire was accidental and caused by hot works which were being carried out to the areas above the windows of one of the houses.