Twenty fire engines and around 125 firefighters tackled a fire near Carshalton Road in Mitcham.
Station Commander Jim Berry, who attended the scene, said: "Firefighters have worked hard this evening and have now brought this fire in Mitcham under control.
"At its height, the fire affected a workshop, a scaffolding yard and part of a house. Around half of the site remains alight. Multiple hotspots also remain alight across around eight hectares of shrubland and grass. Thankfully, there are currently no reports of any injuries.
"Firefighting operations will continue overnight as crews fully extinguish the fire and dampen down hotspots, so please continue to avoid the area if you can. Road closures are in place on London Road and Carshalton Road at the junctions of Willow Lane, Goat Road and Hackbridge Road."
To support firefighting efforts, one of the Brigade's Terrain Support Vehicles was sent to the scene. The vehicle provides off-road capability enabling the transportation of additional equipment closer to fires on open ground. Each vehicle carries approximately 475 litres of water, a backpack blower, ear defenders, beaters and misting lance technology, which allows firefighters to pump water and drive, enabling them to tackle grass fires more quickly and safely.
One of the Brigade's 32-metre turntable ladders was deployed to the scene to help fight the fire from above. The Brigade's Drone Team also attended the scene to provide an aerial view of the fire.
Control Officers took the first of over 100 calls at 1627 and mobilised crews from Mitcham, Wallington, Norbury and surrounding fire stations to the scene. The fire was under control by 2028.
The cause of the fire is under investigation.