The 46-year-old worker broke three vertebrae, his right shoulder blade and several ribs in the fall at a property undergoing redevelopment in west London last February.
The married father-of-four is unlikely to be able to return to manual work as a result of the injuries.
Westminster Magistrates’ Court heard that he was carrying out insulation work on a flat roof for Shoreditch-based Sherlock Interiors Contracting Ltd.
He fell through one of the roof lights and six metres to the ground below.
An HSE investigation found that hard-board coverings previously installed over the roof lights had been removed and replaced with thin plastic sheeting.
Safety decking beneath the roof – designed to protect workers in the event of a fall – was also no longer in place when he started work.
Sherlock Interiors Contracting of London, N1 was fined £8,000 and ordered to pay £5347 in costs after pleading guilty to breaching safety regulations
After the hearing, HSE inspector Peter Collingwood said: “Fragile roof covers provide little or no protection, and should be viewed with the same level of danger as an open void.”