Six fire engines and around 40 firefighters tackled a fire on Dawlish Avenue in Perivale.
A small part of the sixth floor of a 15-storey building under construction was damaged by the fire. Around 30 people left the building before the Brigade arrived. There were no injuries reported.
The Brigade was called at 1209 and the fire was under control at 1305. Fire crews from Wembley, Ealing, Northolt, Park Royal, Southall and Acton fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.