Mirvac slashes construction time by 25pc in pre-engineered townhouse trial
Suppliers of prefabs to builders may take on significant risk in the form of the products they offer, and banks may be wary of releasing funds early for products that may not be built to specification.
But NSW Construction Commissioner David Chandler warned in 2018 that unless Australia developed viable local capacity for prefab supply, it would lose 200,000 local construction jobs to overseas suppliers.
As we increase our scale and volumes, we will begin to see the benefits from a cost perspective. But for now, it’s line-ball.
— Stuart Penklis of Mirvac
Mirvac began installing prefabricated bathroom modules in its apartments years ago and it took five years to refine the process and products to the level where they have now become a standard feature, Mr Penklis said.
It takes time to do things right. Tullamore’s test was for just four homes and the 16-home stage one of the Georges Cove project from Mirvac to Sydney’s Moorebank is expanding the process to 16 homes. At Georges Cove, the company has reduced the time between the start of construction and lockdown – when the roof is up and the structure is watertight – from 25 weeks to just 12 weeks.
But it’s from the next venture, the 300-home Riverlands project, on the site of the former nearby Milperra Golf Club, that the company aims to combine prefabricated walls, floors and bathrooms to maximize the work done in the controlled environment of a factory and reduce on-site construction.
Achieving scale was crucial, especially since prefab meant spending money up front on materials, Penklis said.
“But actually that’s countered by the fact that your build programs are shorter,” he said.
“As we increase our scale and volumes, we will start to see the benefits from a cost perspective. But right now, it’s probably line-ball.
He said he could not foresee the benefits of building large-scale prefab townhouses, but the Tullamore project showed that prefab reduced labor hours by 11% compared to the equivalent conventional construction process. Labor costs are usually 50% of the cost of housing.