The couple were told they needed only to build a hand rail around the balcony to meet the code of compliance at the time, something they thought could be done in no rush.
But after building regulations changed in 2004, the house failed its final inspection on multiple counts.
They thought they could overcome the problem by seeking a determination through the Department of Building and Housing, which only served to realise their worst nightmare. When the department sent an engineer to carry out a full assessment, cladding was removed to reveal that more than half of the house's untreated timber framing had been rotting for years.
This week, the family received an email from the department stating they would need to complete support work on five walls or they would have to leave.
Yesterday, a council officer served them a notice declaring the house a dangerous building and gave them two weeks to either fix the problem permanently or install temporary structural supports.
"I'm beginning to wonder if we'll even be able to get an engineer in within two weeks," Ms Radford said. "[The officer] said he was so sorry about 15 times, and that it was the first time he'd ever had to do it, but there was nothing he could do for us."
Unable to take legal action against the council or Government - and ineligible for the council support package - she and Mr Roberts face the heartbreaking choice of either going ahead with the repairs or tearing their house down to start anew.
Ms Radford said either option would likely stack $300,000 on top of their $150,000 mortgage and mean they might have to move in with relatives for a long time.
"If it looks cheaper to demolish it and start again, that's what we may have to do. We are both 52, and you just don't want a mortgage like that at this time in your life."
The house was a labour of love for the couple, who contracted a private builder for the job.
"My husband worked late nights and weekends ... Really, we put everything into it," Ms Radford said. "Like a lot of Kiwis, it's your sole investment, and we are just average New Zealanders."
She said the crisis had come at a time when they were still supporting children and needed stability to help them through to retirement.
Tauranga Mayor Stuart Crosby said consideration needed to be given to health risks in leaky homes and other dangers posed by poor structural integrity.
Mr Crosby said cases such as the couple's were rare in Tauranga.
"It's a sad occurrence, but unfortunately the council had no choice."
The family have applied for help under the new leaky-homes financial assistance package, which grants Government and council money equivalent to up to a total of 50 per cent of repair costs in return for homeowners promising not to sue their local council for its role in approving their dwellings.
The Government expects its share of the deal will be about $1 billion over five years, based on an estimated 70 per cent of eligible homeowners taking up this package.
Repair costs covered under the package include full demolition and rebuild, design work, project management, building and resource consent fees, valuation fees needed for getting a loan and the cost of alternative accommodation and furniture storage up to a capped maximum.
