Vasile Ionel Vatca was working on a major refurbishment project at Eaton Mews North in Belgravia last March.
Work included the construction of a basement, and a roof replacement.
Vatca was coming down from the roof after clearing up debris when he fell.
Safety inspectors discovered that scaffolding to prevent falls had been removed the previous month.
Westminster Magistrates’ Court heard that Vatca was climbing down a ladder which fell away from the building.
He lost his footing and fell about seven metres, suffering a broken leg, heel and wrist.
He was hospitalised for a week and is now registered disabled.
After the hearing, HSE inspector Andrew Verrall-Withers said: “Companies have a duty to take steps to reduce risks and prevent falls using equipment such as guardrails and working platforms, or even nets and airbags if needs be.
“If the company had properly planned and organised the work and sufficiently assessed the risks of working at height, along with the use of appropriate work equipment – the likelihood of this happening would have been much reduced.”
R & G Construction Ltd of College Road in Harrow pleaded guilty to safety breaches and was fined £30,000 and ordered to pay full costs of £7,515.