From October next year, all new homes will need to meet accessibility and energy efficiency requirements in many parts of Australia.
Queensland's peak industry body, Master Builders, said they anticipated the changes would add an extra $30,000 to an average build.
"It's the first homebuyers who are most impacted, who are struggling to get a deposit together, to make the repayments, and then the cost of construction goes up," Master Builders CEO Paul Bidwell said.
"$30,000 is a significant amount."
Under the changes, homes built in Queensland would need to meet a seven-star energy-efficiency rating and be more accessible with at least one step-free entry.
State government modelling suggested the combined cost would be $6,000.
"What we know is that, on average, it is likely to increase building costs by around 1 per cent," Minister for Energy and Public Works Mick De Brenni said.
"We must also remember that that is between 14 and 20 times cheaper than the cost of modifying homes after they are built."
A meeting of building ministers on Friday voted to adopt the changes from October 2022, with a 12-month transition period.
However, New South Wales, Western Australia and South Australia had previously indicated they would opt out of the new code.
Accessible home advocates said they had been discussing these changes for two decades and the move was well overdue.
Margaret Ward, convener of the Australia Network for Universal Housing Design said: "We took much longer than we should have".
"There was a lot of misunderstanding about what this means and there were governments that were simply not interested in the idea and the housing industry had undue influence," she said.
But Mr Bidwell criticised the time frame.
He said it would place additional strain on an industry already struggling with a 30 per cent increase in supply costs, and a pipeline of work beginning to slow.
"It's breathtakingly stressful," he said.
"[Builders] are going to have to change the way they do their business.
"October 2023 is not that far away and right now they're dealing with all sorts of other pressures.
"They just don't need that now."
Just how different will home design be?
Under the changes, new homes would need to be built to a "silver standard" of accessibility.
This meant, in addition to at least one step-free entry into the home, increasing the width of internal walkways to fit a wheelchair or walking frame, and a toilet on the entry level.
"The changes are critical," Ms Ward said.
"The United Kingdom did this in 1999.
"Everyone from the ministers down has come to terms with the fact we need to have housing in the future that will be inclusive of all people, older people, pregnant women, little children, that all these folk can be safe in their own homes."
Mr De Brenni said they had taken a commonsense approach to the changes, with exceptions for places in north Queensland.
"There are sensible exemptions from the accessible housing provisions for steep blocks, for homes that are built on stilts to accommodate overland flow from heavy rainfall," he said.
"Those exemptions mean that iconic designs like the Queenslander with a set of stairs at the front will be exempt from some of the provisions."
Double-glazed windows, more rooftop solar and lighter-coloured roofs and walls were among the energy efficiency measures required.
The new code was expected to reduce emissions by 1.64 million tonnes and would assist in Australia reaching its goal of net zero by 2050.
It was anticipated the changes would save the average household $185 a year in power bills.
Master Builders said the cost-benefit analysis done by the Australian Building Code did not add up.
"It failed," Mr Bidwell said.
"The costs exceed the benefits on both the energy efficiency and accessible housing.
"It beggars belief that the Australian Building Code board have recommended this and the ministers have supported it."
Meanwhile, advocates would now focus their attention on pushing for a higher "gold standard" for accessibility.
"With tenacity, ordinary citizens can make change," Ms Ward said.
"It was the ordinary people trying to build ordinary homes that would fit their families now in the future and it will be that group that will speak out again."
