The builder behind Sydney's Opal Tower has lodged a counter-claim in a NSW court, blaming the engineer for the cracking that caused the tower's evacuation and repair bill of more than $30 million.
In the latest development in the continuing saga, Icon, the builder of the tower, has lodged documents in the NSW Supreme Court alleging the cracking and damage was caused by "shortcomings" in its design.
It alleges WSP Structures, the global engineering firm behind the $170 million apartment complex, prepared and approved all relevant structural designs.
As the builder, Icon alleges it undertook construction based on WSP's designs, which it says were faulty.
The allegations are part of a counter-claim in response to the class action suit lodged in the NSW Supreme Court by Opal Tower residents in July.
Owners of units in the tower are seeking millions of dollars in compensation from the Sydney Olympic Park Authority, a NSW government-owned organisation.
SOPA is the target of the lawsuit as it is the owner of the land on which the Opal Tower sits and considered a "developer" under state government law.
The class action suit claims a "breach of warranty" and that the design and construction of the complex, which was evacuated on Christmas Eve 2018 after residents spotted cracks in its foundations, was not designed or constructed with "due care and skill".
The lawsuit – which is set to be heard for an update in the Supreme Court on Friday – has turned into a blame game, with SOPA's own counter-claim pinning the building's problems on Icon.
Icon has rejected those claims and moved the blame on to WSP.
Who is responsible for the structural faults that caused the evacuation and more than $30 million repair bill – that Icon has paid for – will be a critical part of the class action suit.
Claims of 'misleading' conduct
It is understood Icon is referring to parts of the Opal Tower final report, released by the state government in February, which outlined numerous key construction and material deficiencies, particularly the design of a critical hob beam that burst under pressure.
In its claim it alleges WSP engaged in "misleading or deceptive conduct" and Icon's own construction works "did not causally contribute to that damage, or the extent of it".
The ABC contacted both WSP and Corrs Chambers Westgarth – the firm that triggered the class action suit – for comment.
Icon has declined to speak specifically on the counter-claim ahead of Friday's court hearing. However, the company's managing director Nicholas Brown said from "day one" it had been trying to find out what happened to prevent similar events in the future.
"While it won't undo what happened, today's developments are an important step forward for Opal tenants and owners, our business and employees," he said.
"We will continue to work towards the return of the residents back into the remaining apartments at Opal Tower."
The ABC understands about three to five apartments owners of the 392-apartment tower are still locked out of their homes following the rectification works, which are being carried out by Icon.
The number of parties involved in the suit – which, along with WSP, SOPA and Icon includes the developer Ecove – means it is expected to go well into next year before a resolution.