Six fire engines and 35 firefighters and officers were called to a fire in a derelict workshop on Allum Way in Whetstone on Saturday morning.
The blaze damaged part of the property’s ground floor, first floor and roof.
The Brigade was called at 0823 and the fire was under control by 1219. Crews from Barnet, Finchley, Southgate and Hendon fire stations attended the incident. The cause of the fire is under investigation.