The principal of Auckland's Green Bay High School has added her voice to those of other principals warning that taxpayers face a huge cost upgrading the country's schools.
School principals say they are facing a perfect storm of property problems with many classrooms past their use-by date and billions of dollars are needed to fix them or build new ones.
Green Bay High School has just demolished three relocatable classrooms deemed too old to be used again.
They were in place for several years while the school renovated its 40-year-old maths block, which principal Morag Hutchinson said was past its use-by-date and needed upgrading.
She said the matter of upgrading was much more complex than what it used to be.
"Twenty years ago you might do a lick and a promise and a tidy up and carpet, and perhaps fix the roof. These days you have to really think about the way in which teaching and learning is happening," she said.
"So you're looking at a much more complex upgrade; so it might be taking out walls, changing the shapes of classrooms and certainly putting in a significant level of ICT (Information, Communication and Technology) infrastructure."
The added complexity brings with it added cost, making the burden of renovating even higher.
"Anybody that's renovated their own home knows that the cost of rebuilding these days is more expensive and we also have higher standards around things like warmth - the double glazing, and being mindful of building something that's kind to the environment. By the time you add those elements in you're talking about a much more expensive build.
"Schools fundraise obviously for the icing on the cake but the cake itself is funded by the tax payers and I think that the call on the public purse around public buildings - and schools are in that category - it's a bigger call now than what it once was. And nobody wants to pay any more taxes do they."
The added costs were not helped by the high renovation demand. Sixty-eight percent of schools are between 30 and 100 years old, and most are over 50 years old - meaning they have high maintenance costs and some need complete replacement.
To make matters worse, there are not enough buildings. The school-age population is growing, and it needs $1.3 billion in new school buildings over the next decade.
The problem needed to be solved now, Ms Hutchinson said.
"Auckland's population for example is bursting at the seams and so of course there's going to be more and more pressure on, and wear and tear on, the existing buildings.
"Needing to think about the way in which we're going to pay for that is quite scary because we've still got to pay for the existing buildings that are in maybe areas where population growth isn't occurring. I think we all know that there are examples of buildings that have fallen into disrepair and really are unfit for purpose in other parts of New Zealand."
She said it was a long-term problem for the Ministry of Education.
"Everything can be solved with a bigger spend but we're all competing for the same tax dollars.
"I can't see where the solution is unless everyone is happy to pay more for public buildings. So it's schools, hospitals, it's the same question isn't it."