Giovanni Mastrodomenico, 56, from Swindon, fell through a waterproof membrane into the unguarded hole while working at the Marlborough Park development in the town on 31 August 2011.
His employer Tego Roofing Ltd, of Oxford, and principal contractor Wates Construction have been prosecuted following the incident.
Swindon Magistrates’ Court heard that Mastrodomenico was carrying out metalwork prior to the installation of a vent on the roof of the new apartment block. The hole he plunged through was where the vent was to be placed.
He fell four metres onto a concrete floor below, causing permanent injuries that have left him unable to walk and confined to a wheelchair.
An HSE investigation found that scaffolding under the hole inside the building had been removed because it was obstructing an emergency escape route, and that scaffolding planks had subsequently been placed over the hole instead.
But these planks were in turn removed to allow workmen to lay a waterproof membrane over the hole in preparation for the vent to be installed leaving nothing in place to prevent Mastrodomenico’s fall.
The court was told that the risk assessment and method statement for the work was unsuitable and insufficient because it failed to refer to the installation process for the vent.
There was confusion about who the site supervisor was when the incident happened and, although the site manager had seen the roofers working near the hole, he did not stop the work or ensure the scaffolding boards were replaced.
HSE established that Tego Roofing failed to provide adequate supervision or instruction to its employees while working on the roof.
Wates failed to plan, manage and monitor the work and did not ensure there was a risk assessment in place.
Tego Roofing Ltd, of Chalgrove, Oxford, was fined £10,000 and ordered to pay £9,460 in costs after pleading guilty to breaching CDM regulations.
Wates Construction of Leatherhead, Surrey, was fined £18,000 with costs of £11,127 after also pleading guilty to a separate breach of the same regulations.
Speaking after the hearing, HSE Inspector Keiron Jones, said: “Mr Mastrodomenico’s life and that of his family have been completely changed by the management failings on the site.
“Apart from the pain and suffering he has gone through, his employment opportunities are now restricted and he will never be able to walk again.
“Construction companies and their contractors must have proper plans in place to allow their employees to complete the job safely.
“As principal contractor, Wates failed to plan, manage and monitor the work, and ensure there was a risk assessment in place.
“Tego also failed in their duty to provide a risk assessment, ensure there was adequate supervision on-site and make sure there was a safe system of work for the installation of the vent.”