Six fire engines and around 40 firefighters responded to reports of a fire at a detached house on Alexander Avenue in Willesden Green.
The roof was destroyed and half of the first floor was damaged by the fire. Two people left the building before the arrival of the Brigade. There were no reports of any injuries.
Firefighters used one of the Brigade's 32-metre turntable ladders as a water tower.
The fire is believed to have been accidental and caused by hot works on the roof. Hot works tend to involve an open flame and are activities that can produce heat and sparks capable of starting a fire.
The Brigade was called at 1923 and the fire was under control by 2016. Firefighters from North Kensington, Willesden, Paddington and surrounding fire stations attended the scene.