Passing tradie among heroes who pulled man from burning home

Neighbours have used a sledgehammer and crowbar back to break down the door of a burning home at Klemzig in Adelaide, pulling the resident inside to safety.

Dozens of local residents and workers called emergency services when they noticed a huge amount of smoke billowing from the house on Hender Avenue just after 1pm.

Thomas Hocking, a passing tradie, was among those who saw the flames and leaped into action.

"Somebody yelled at me and said there was somebody was trapped so I ran to the car and got a crowbar and a sledgehammer, ran over to the front door and started smashing it," said Mr Hocking.

"I got the screen door open. Unfortunately I didn't have enough breath in me to open the other door but somebody else grabbed it and smashed the door open and saved the guy's life."

The resident - a man in his 50s - was unconscious when he was dragged out of the home and suffered serious burns.

He's been rushed to the Royal Adelaide Hospital in a critical condition.

The house was destroyed with damage estimated at $450,000.

Fire cause investigators are yet to determine what sparked the blaze.