Canterbury Magistrates heard that the development site in Ramsgate, run by Ecobuild Homes Ltd, had been visited by safety Inspectors seven times in five months.
On visits between July and November 2012,inspectors were forced to immediately stop work once, serve three prohibition notices and two improvement notices.
The site manager on the restaurant-to-flats job was also issued with a prohibition notice because the operation of the site was far below minimum legal safety standards.
HSE found issues relating to fire safety, accumulation of rubble, debris and bricks falling into a neighbouring property, and site security.
Ecobuild Homes Ltd, of Ashford, Kent, was found guilty in their absence of safety breaches.
Magistrates fined the company, which had failed to appear at court for the second time, a total of £40,000 and ordered them to pay costs of £10,035.
After the hearing, HSE Inspector Caroline Penwill said: “There were elements of this development that had evidently become a shambles – but a dangerous one.
“If HSE visits a construction site and has to issue prohibition notices preventing further work, that in itself shows that there is a very real and immediate risk to workers there, and possibly to members of the public.
“Ecobuild Homes Ltd failed on several fronts to safeguard the workforce from risks that are well known in the construction industry. They either did not identify those risks or neglected to manage them effectively.”