Anthony Nightingale, 34, of Copdock, Ipswich, was filmed using a petrol-powered disc cutter to cut through a tile while he and an employee worked on the roof without any fall protection.
Mr Nightingale was prosecuted in his capacity as director of 3A Roofing Ltd by the Health & Safety Executive (HSE) after a concerned member of the public spotted the unsafe work at Dennington, Suffolk last July and reported it to the HSE.
Ipswich magistrates heard that Mr Nightingale failed to use a suitable roof ladder to reach the ridge and instead he and his employee clambered up and down the tiles. They were seen walking along the ridge where there were no measures in place to prevent them from falling off the roof.
Anthony Nightingale pleaded guilty to a breach of the Work at Height Regulations 2005 and was fined £1,300. He was also ordered to pay £3,000 in prosecution costs and a £15 victim surcharge, the proceeds of which will be spent on services for victims and witnesses.
HSE Inspector Elizabeth Fowle said after the hearing: "Mr Nightingale should have led by example, but instead he put his own life and the life of an employee at risk. Fortunately no one was injured on this occasion, but it is astonishing that Mr Nightingale thought it was acceptable to use a potentially dangerous piece of machinery while perched at the top of the roof.
"This case should serve as a warning to other company directors that if you work without the right safety equipment and put lives at risk, you could end up in court."