The cladding system at the centre of multimillion-dollar lawsuits has been vindicated after a years-long court case involving 144 homeowners.
In the second setback for homeowners suing James Hardie in as many weeks, the High Court in Wellington found the Harditex product was not a cause of weathertightness issues.
The court issued a statement this morning outlining a new judgment, less than two weeks after a massive Auckland High Court class action was settled out of court.
The High Court at Wellington said James Hardie owed homeowners a duty of care, but found homeowners hadn't proved Harditex caused the weathertightness issues.
The case was sometimes referred to as the Cridge Litigation.
In a press release, the court said James Hardie gave sufficient technical assistance and this guidance was properly directed to "the reasonably competent builder".
"The court found that the product, assessed against established building science, was not flawed in its design, had been adequately tested and had independent endorsement."
It also said Harditex was not proved to be materially different from sheet cladding products that preceded it.
The court's conclusion was that the inherent flaws alleged were not proved, and the sheet was a conceptually sound product.
The product could be installed in a way that would provide a weathertight house, the court found.
In a statement, James Hardie said it was pleased with the outcome, and was sympathetic to the troubles of leaky-home owners.
"The company notes that the plaintiffs have the right to appeal the court's judgement in the Cridge litigation," the company's Australia and New Zealand country manager John Arneil said.
Justice Simon France said Harditex was produced and marketed in New Zealand from 1987 to 2005.
"The period through which Harditex was on the New Zealand market coincides, most certainly in its later stages, with New Zealand's leaky-building crisis," he said.
"At its most general, the question this case raises is what role, if any, Harditex played in the crisis."
Four homeowners from Karori and Island Bay led the proceedings but more than 100 others opted in.
The homeowners challenged the suitability of Harditex cladding, and the method by which it had to be installed.
As happened in the Auckland High Court class action, the Cridge arguments included claims the Harditex cladding was too difficult for builders to get right.
Justice France in his new judgment said there was less experience generally in the building sector with sheet cladding than with timber weatherboards and brick.
"So, as sheet cladding became more popular, so there was a decline in the percentage of builders familiar with the cladding they were working with."
Justice France said, in general, reasonably competent builders could and did use Harditex to build sound, waterproof houses.
In recent lawsuits, the James Hardie entities have argued that incompetent builders and industry deregulation were to blame for some leaky housing issues.
"Anyone with exposure to the emotional and financial impact a leaky home can have
on the people involved can only have the greatest sympathy for those caught up in
such a situation," Justice France said.
"It is undoubtedly a miserable and stressful experience."
But he said it was crucial to emphasise this was an adversarial case where the outcome reflected the court's assessment of the evidence.