Four fire engines and around 25 firefighters tackled a fire at a semi-detached house on Burnside Avenue in Chingford.
Most of the ground and first floor were damaged by the fire. Five people left the building before the Brigade arrived and were treated on scene by London Ambulance Service.
Control Officers took the first of four calls at 0854 and mobilised crews from Walthamstow and Chingford fire stations to the scene. The incident was over for firefighters at 1005.
The cause of the fire is under investigation.