Six fire engines and around 40 firefighters were called to a fire at a scaffolding yard on Mitcham Road in Croydon.
A large quantity of scaffolding boards were damaged by the fire. There were no reports of any injuries.
The Brigade was called at 1230 and the fire was under control by 1738.
Fire crews from Croydon, Norbury, Wallington and surrounding fire stations attended the scene.
The cause of the fire is believed to be accidental following controlled burning.