WATES was alerted to the dangers of a fragile roof at its Woolwich Arsenal site in south-east London before a worker fell 11 m to his death.
The contractor was fined £150,000 at the Old Bailey last week following the death of Indergit Singh in June 2000.
The court heard how subcontractors on the site had complained about the inadequate protection around roof lights on the building being developed at the Royal Artillery Museum.
Wates agreed that improvements were needed but failed to suspend work while they were carried out.
Mr Singh fell through a roof light onto the concrete floor and died from his injuries four days later. He was working for a subcontractor on the roof, which had a wired glass roof light running along the full length of the building on each of the four pitches.
The court also heard that Mr Singh had not received a formal site induction and that no risk assessment nor method statement was prepared before work started.
HSE inspector Richard Boland said: 'This was an entirely avoidable death.'