Matthew Fuller was working in a ceiling and was believed to have struck the mains power.
The father of the first insulation installer to die under the failed home insulation program holds former prime minister Kevin Rudd responsible for his son's death.
Kevin Fuller, whose son Matthew died on October 14, 2009, said in his statement to the commission that he considered "Rudd to be one of the main people responsible for Matthew's death and the deaths of three others".
Mr Fuller also described Mr Rudd's behaviour as "a disgrace" when he met him in Canberra in March 2010.
"I hold Kevin Rudd to be one of the main people responsible for Matthew's death and the deaths of three others," Mr Fuller said.
Mr Fuller said he had travelled to Canberra to meet with then-climate change minister Greg Combet.
He said "a white haired gentlemen burst in and disgraced himself".
"By this time I had read enough documents obtained under Freedom of Information and heard enough ministerial statements to form my own beliefs about the role he played in the design and administration of the HIP," Mr Fuller said.
"I did not want to meet him. His whole attitude and demeanour was wrong in that meeting.
"It was very uncomfortable having him burst in and try to take over. I told him some home truths and apologised to Greg Combet and we left that meeting to go and meet opposition leader Tony Abbott."
Mr Fuller said Mr Rudd forgot his first name during the meeting, even though they share the same one.
"I think he was in a rush ... and I think he wanted to be seen to have seen us," Mr Fuller said.
He said Mr Combet was "very sincere, open and made us feel comfortable".
Mr Rudd, who gave evidence at the inquiry on Thursday, said he accepted "ultimate responsibility" for the failed scheme, but said he was never made aware of the inherent safety flaws in the program.
But Mr Fuller said Mr Rudd's words meant little to him.
"I think over time he truly starts to believe that he was sorry," Mr Fuller told reporters outside the court.
"Nothing is going to bring Matt back, or the other boys."
Matthew was the Fullers' only son, after their first was stillborn.
"Matthew was desperately wanted and a much-loved and cherished child," Mr Fuller said.
In the wake of Matthew's death, Mr Fuller said he wrote to ministers, state and federal, pleading for something to be done about the insulation scheme.
"Just as a father and just as an Australian I expected the system to get off its arse and go and sort, go and change things and make things happen."
He said the deaths of the other three installers, "nearly killed him".
Frustrated with the lack of action, Mr Fuller pushed for the royal commission to examine the program in its entirety.
"We've met with three prime ministers, two opposition leaders and god knows how many ministers and their advisers," Mr Fuller said.
"I shouldn't have to do that ... that's not a good thing for me to have to do. I should be able to talk to them once ... they should then take on that fight."
Mr Fuller said he was concerned 13,659 homes with foil insulation installed under the program had not been inspected since the scheme ended.
On a law of averages, he said, that meant as many as 376 roofs were potentially "alive".
"To me, that's not acceptable," he said.
Mr Fuller had the final word at the royal commission in Brisbane on Friday, saying he had been on a crusade for justice for his son, and the three other insulation installers killed during the program, for four years, seven months and two days.
"It really shouldn't be that hard for some individual to get justice," he said.
Matthew Fuller was electrocuted just five days after staring work in the insulation industry.
Mr Fuller said his son had met the love of his life and wanted to earn enough money to move into his own place with his girlfriend.
He was "cannon fodder" for the insulation program, Mr Fuller said.
"We will never, ever be able to forget what the HIP did to us, needlessly killing our only son," he said.