The company had pleaded guilty to a breach of regulation 6 of the Construction (Health, Safety and Welfare) Regulations 1996 at a previous hearing.
Robert Pettigrove, 42, fell about 20 ft from the edge of the floor slab of a building being demolished by Lock Brothers in Willowbrook Road, south-east London. He survived the fall but has been unable to work since.
Pettigrove was employed as a lorry driver by a firm in Potters Bar, Hertfordshire, and was visiting the site when the incident happened.
The court found that the company had failed to take suitable and sufficient steps to prevent people from falling when working at height.
Principal health and safety inspector Neil Stephens said the accident could have been prevented easily.
He added: "This case highlights the need for the industry to ensure that it puts more effort into preventing falls from height."