Beverley Magistrates court heard how, on 27 March 2015, an operative was installing a flue system for a biomass heating system at a farm in North Yorkshire.
He had attempted to work from a ladder at the side of the outbuilding but when this proved ineffectual, he resorted to climbing onto the roof to complete the works.
Whilst working on the roof, the operative fell a distance of around 2 metres through the fragile cement sheet, suffering injuries including broken bones in the left ankle.
An HSE investigation found the company had failed to adequately plan the installation of the heating system and the necessary work at height.
The investigation also found the company failed to provide suitable work at height equipment such as a mobile elevated work platform, edge protection, crawl boards, a roof ladder or scaffolding.
Duncan Plumbing Heating and Electrics Ltd of Tockwith, North Yorkshire pleaded guilty to safety breaches and wasn fined £32,000 and ordered to pay £2,424.60 in costs.
After the hearing, HSE inspector James Harvey said: “Work at height, such as roof work, is a high-risk activity that accounts for a high proportion of workplace serious injuries and fatalities each year.
“This case highlights the importance of following well-known industry guidance to plan and assess the work at height requirements needed to complete the work safely.”