Six fire engines and around 40 firefighters tackled a fire at a disused workshop on Beddington Lane in Beddington.
Most of the building was damaged by fire. There were no reports of any injuries.
A London Fire Brigade spokesperson said: "The use of one of the Brigade's 32 metre turntable ladders was vital in helping to bring the fire under control, as the building was too unsafe for crews to enter."
The Brigade was called at 1847 and the fire was under control by 2033. Fire crews from Wallington, Croydon, Norbury, Mitcham and Kingston fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.