Four fire engines and 21 firefighters and officers tackled a house fire on Rathgar Avenue in West Ealing.
London Fire Brigade Borough Commander for Hounslow Greg Ashman said:
"Firefighters worked hard and stopped the fire from spreading to adjacent homes. The whole of the roof was destroyed and part of the ground and first floor as well. Thankfully there were no injuries."
Three workmen left the house before fire crews arrived. A further four people from an adjacent property also escaped unhurt.
The Brigade was called at 0938 and the fire was under control by 1135. Fire crews from Acton, Southall and Hayes fire stations were at the scene. The cause of the fire is under investigation.