The men had been investigating a leak in the flat roof at Barlow Moor High School when one of them leant on a wooden handrail that collapsed. The other worker tried to grab hold of him, but they both ended up falling to a scaffolding platform with protruding metal poles more than one-and-a-half metres below.
Warrington-based Cruden Construction Ltd, the principal contractor on the site, was prosecuted by the Health & Safety Executive (HSE) following the incident at the school on Parrs Wood Road in Didsbury on 6 September 2011.
Trafford Magistrates' Court heard that the two men had been working approximately three metres above the ground as part of a major refurbishment project at Barlow Moor High School.
One of the workers, aged 59, from Hightown, Merseyside, twisted his right knee and suffered bruising to his ribs and left arm when he fell onto the scaffolding platform.
His colleague who tried to save him, aged 42 from Middleton, Greater Manchester, suffered a fractured rib, and bruising to his arm and chest.
The court was told both workers were lucky not to have been impaled on metal poles sticking up through the scaffolding when they fell.
Cruden Construction pleaded guilty to breaching the Work at Height Regulations 2005 by failing to ensure the hand rail was a sufficient strength and rigidity for the work.
The company, of Knutsford Road in Grappenhall, was fined £6,500 and ordered to pay £2,530 towards the cost of the prosecution.
Speaking after the hearing, HSE inspector Laura Moran said: "Both men were lucky to escape with relatively minor injuries after they fell from the roof at Barlow Moor High School. They could easily have been seriously injured or even killed had they been impaled by a scaffolding pole, or fallen all the way to the ground below.
"The wooden handrail that Cruden Construction provided simply wasn't up to the job and their safety was compromised as a result."