Older people stuck in leaky homes have been especially vulnerable to health problems and financial stress that has come with the saga, a new study finds.
It's estimated about 80,000 homes and apartments built between 1991 and 2005 used products and methods that have not proved weathertight, of which about 12,000 have been repaired privately or with the help of government assistance.
One leaky homes specialist lawyer this month said as many as 90 per cent of standalone leaky homes were likely still rotting.
Now, a paper by three researchers has identified older homeowners are especially vulnerable to the negative effects.
Using interviews, housing sales and institutional analysis, the authors found that older homeowners faced issues over the use and financial value of their homes which had negative impacts on retirement planning, relationships and physical and mental health.
Further, they found that, because of age-related frailty or existing health conditions, older people had a higher health risk from living in a damp, mouldy environment.
They also faced increased risk of depression and anxiety, as well as stress from irreparable damage to their homes.
Since older homeowners were mostly reliant on superannuation, most of their wealth was tied up in their home, causing increased financial stress.
"The public implications of the weathertight homes market failure as it relates to older people go beyond a simple framing of the public interest in the failure of the building industry," the authors concluded.
"Instead, this paper has shown that the impacts for older people include reduced material, physical and mental well-being, loss of connections with others and declining ability to look after themselves and other dependents."
Co-author Dr Michael Rehm, a property researcher at the University of Auckland, said that in some cases, older homeowners' nest eggs had "been essentially evaporated".
"Most of the people interviewed were owner-occupants in a leaky home and they were all people who were trying to gear up for retirement and make plans and this completely derailed them, really."
Rehm said the issues identified in the study had been expected by him and his colleagues, lead author Dr Bev James of Public Policy and Research and Kay Saville-Smith of the Centre for Research, Evaluation and Social Assessment.
"We knew it was all going to be unpleasant, but it was good for these people to get these things off their chest and have somebody to talk to about it," he said.
One big concern raised by the study was that many older people found it difficult to use the services set up by authorities.
"A lot of them, because they are older, don't have a lot of technical savvy, and it became very clear that the systems the Government really tried to help with were almost impossible for these people to navigate."
Rehm said other research he'd led had also found that negative buyer stigma around homes built with monolithic cladding types persisted, even in heated property markets like Auckland's.