Four fire engines and around 25 firefighters tackled a fire at a terraced house on Durley Avenue in Pinner.
Part of the first floor was damaged by the fire. There have been no reports of any injuries.
One of the Brigade's 32-metre turntable ladders was used at the scene to help fight the fire from above.
Control Officers took the first of two calls at 1537 and mobilised crews from Harrow, Northolt, Ruislip and Stanmore fire stations to the scene. The incident was over for firefighters at 1631.
The cause of the fire is under investigation.