The New South Wales building commissioner had reported a building site over safety concerns only a day before part of a home completed by the same company partially collapsed.
Three people had a "lucky escape" from a six-to-12-month-old home at Condell Park in Sydney's south-west in the early hours of Good Friday, when one corner of the house above the garage collapsed, Fire and Rescue NSW said.
A New South Wales Fair Trading spokesperson said an investigation into what happened is ongoing, and the builder, Hemisphere Constructions, said they "remain able and willing to rectify the damage".
"We have maintained an excellent track record in construction and this incident is deeply distressing to our staff, contractors and family," the company said in a statement to the ABC.
"We will work with the relevant authorities to undertake an investigation into what has occurred.
"We have been in contact with the home owner and family to understand how we can support them during this difficult time, including to offer temporary accommodation, hire car, storage facilities, removalist and many more for the family affected."
However, only a day before that collapse, the state's powerful building commissioner David Chandler had made an unscheduled visit to another property being built by the same company at Concord in Sydney's inner west.
Following the inspection, Mr Chandler reported the site to both SafeWork NSW and Fair Trading over safety concerns.
"It was pretty obvious the number of unsafe work practices that were exhibited there from people not wearing PPE, no handrails on scaffolding where there could have been serious falls," he told the ABC.
"There is a strong correlation between unsafe worksites and the potential for serious defects to be incorporated in the project.
"So the project will now attract a safety inspection, and it will attract a building compliance inspection because these two things go hand in glove."
Mr Chandler said he anticipated the audit process would likely take about six to eight weeks, after which a draft report would be issued to the builder, and it would have an opportunity to make submissions to that report.
After that, the company might be issued a stop work order, a prohibition order or a building works rectification order, the commissioner added.
In a statement, Hemisphere Constructions said that, after the commissioner's visit, they sent all tradespeople home.
"The building commissioner … saw form workers working on the deck above. We have since sent all trades home and rectified the site with all railings and within SafeWork NSW standards."
A spokesperson for SafeWork NSW said they had issued notices to Hemisphere Constructions last week.
"A request for service was … received by SafeWork NSW about a falls from height risk at the address, and inspectors attended the site and issued prohibition and improvement notices to the developer on 11 April 2023," the spokesperson said.
"Follow-up visits will occur to monitor and ensure compliance with the notices."
In an additional statement sent to the ABC on Thursday afternoon, Hemisphere Constructions said it takes "safety very seriously".
"We have followed all necessary safety protocols and have taken all precautions to ensure the safety of our workers, tenants, and owners of all our properties," the statement said.
"We are committed to delivering high-quality construction work to our clients. Our priority is to ensure that our clients are satisfied with our work and that all safety regulations are met. We understand that safety is crucial and will continue to prioritise this in all our construction works.
"Recently, we have experienced a catastrophic failure in one of our newly built homes, and we have been working tirelessly with the tenants and owners of all our properties to overcome this."
Mr Chandler said this was an example of a wider problem.
"We're seeing more and more builders who have been traditionally involved in single, detached housing or townhouses starting to move some of the business towards building multi-unit apartment development," he said.
"The project at Concord is a multi-unit apartment building, which is a class two building under the legislation, and that's been the priority focus of my reform work for the last four years. So, this particular builder hadn't been visible to me prior to that."
