Ten fire engines and around 70 firefighters tackled a flat fire on Robin Close in Enfield.
Part of the roof and the first floor of the building were damaged by fire. The roof subsequently suffered a partial collapse. Eighteen people left the building before the Brigade arrived. There were no reports of any injuries.
One of the Brigade's 32-metre turntable ladders was used at the scene as an observation platform and to tackle the fire from height.
The Brigade's Control Officers took the first of 12 calls at 1648 and mobilised crews from Enfield, Edmonton, Barnet, Chingford and surrounding fire stations to the scene. The fire was under control by 1838.
The cause of the fire is believed to have been electrical.