The 49 year-old, from Hereford, who has asked not to be named, had been working to convert a garage into a garden room at a home in Westhide, Hereford when the incident occurred on 24 May 2012.
Nunnington-based SC Joseph, was prosecuted by the Health & Safety Executive (HSE) last week after an investigation found the firm had failed to ensure suitable measures were in place to prevent or mitigate a fall.
Herefordshire Magistrates' Court heard that the employee had been working on the roof to install two roof lights. He stepped onto a roofing batten that he had placed across a metre-square hole cut for one of the lights by his colleagues. It gave way and he fell some 3.5m onto the concrete floor below, fracturing his vertebrae. He was off work for eight weeks.
The court was told that the contractor should have put safety measures in place below the open holes in the roof, such as a platform or a birdcage scaffold that would have allowed work from below.
SC Joseph, of Sandalwood, Nunnington, Hereford, pleaded guilty to a single breach of the Work at Height Regulations 2005. The company was fined a total of £4,000 and ordered to pay £1,516 in prosecution costs.