Andrew McElvaney, 52, from Chesterfield, was prosecuted by the Health and Safety Executive (HSE) after the workers were spotted replacing broken tiles on 21 September 2009, without proper safety equipment.
Trafford Magistrates’ Court heard that customers and staff at Frankie and Benny’s restaurant, at Capital Quays on Trafford Road, were also put at risk as the area below where they were working had not been cordoned off.
At one point, one of the roofers was seen working directly above a customer, who was sitting at a table outside the front of the restaurant.
The employees at Mr McElvaney’s company, Shire Building Services, used a tower scaffold to reach the roof but the job required them to work directly on the roof, outside the protection of the scaffold. As a result, the court heard they could have been seriously injured if they had fallen almost three metres to the ground.
Mr McElvaney, of Valley Road in Old Withington, pleaded guilty to breaching Regulation 4(1) of the Work at Height Regulations 2005 by failing to ensure the work was properly planned and carried out safely. He was fined £5,000 and ordered to pay costs of £2,916 on 26 November.
HSE inspector Declan Geraghty said: "Mr McElvaney is lucky no one was seriously injured or even killed as a result of the poor safety standards. The work had not been properly planned and as a result a tower scaffold was the only protection provided.
"The roofers had to work all over the roof to replace a significant number of roof tiles but the tower scaffold could only be used for a small section of the roof. There were also no measures taken to cordon off the area below where his employees were working.
"If one of the workers had slipped and fallen, or a tile had been dropped onto a customer or member of staff, then the consequences could have been fatal."