Health & Safety Executive (HSE) inspectors visited Stefano Di Piazza's construction site at Sun Street, Waltham Abbey, Essex, on 10 February 2010, as part of a targeted programme of construction site inspections and saw contractors working three metres above ground without measures in place to prevent them from falling.
A prohibition notice was served by HSE to stop all work immediately until safety measures were put in place.
Further enquires determined that Stefano Di Piazza of King Edward Road, Waltham Cross, Hertfordshire, was the client for the development.
Stefano Di Piazza pleaded guilty at Chelmsford Magistrates' Court to four breaches of the Construction (Design & Management) Regulations 2007 and was fined a total of £10,000 with £5,741 to pay in costs.
Mr Di Piazza admitted that he failed to appoint a competent principal contractor; failed to take reasonable steps to ensure that work was carried out without risk to health and safety; did not appoint a CDM Co-ordinator and didn't notify HSE of the construction project to convert two buildings into nine apartments and two retail units.
Speaking after the hearing, HSE inspector David King said: "Developers have a big influence on how work is done safely and they have legal duties as the construction client. They have to appoint the right people, provide information to the team and make sure there are suitable management arrangements and a health and safety plan in place.
"Mr Di Piazza blatantly disregarded the importance of a safe working site, leaving the workers at Sun Street in serious and unnecessary danger."