Four fire engines and around 25 firefighters tackled a fire at a building under renovation on Harrow Road in Paddington.
Around two tonnes of building waste were alight on the ground floor. 17 people left the building before the Brigade's arrival. There are currently no reports of any injuries.
The Brigade was called at 1328 and the incident was over for firefighters at 1429. Firefighters from Paddington and Euston fire stations attended the scene.
The cause of the fire is under investigation.