"The court was told there are numerous similar cases awaiting the outcome of this appeal," said Justices Susan Glazebrook, Terence Arnold and Rhys Harrison.
In January, the cost of fixing the growing leaky-school problem was put at about $1.5 billion.
About 160 schools, two-thirds in Auckland, have been identified as having leaky buildings - a worry for Education Minister Anne Tolley.
"It's certainly giving me a few sleepless nights as to how we are going to manage to fund that," she said this year.
Econicorp, trading as Ahead Buildings, put up the Glen Innes school hall and with hall designer LHT, had tried to strike out a claim brought by the ministry on behalf of the school.
Econicorp argued it did not owe a duty of care to the Minister of Education to build the school hall to a workmanlike standard, particularly as the building was non-residential and previous court decisions had found councils did not owe duties to owners of non-residential properties.
The hall was built in the late 1990s and the ministry contributed $237,000 after the school's board applied for most of the money to be paid by the state.
Mr Grimshaw, whose firm Grimshaw & Co acts for about 6000 leaky home owners, said many schools were waiting for this decision.
"It now gives the Government the option of going after those builders who put up substandard buildings, so the Government can try to recover some of the money they are paying out to owners under their new Financial Assistance Package," he said.
The result was also good news for owners of non-residential properties such as schools, hospitals and other buildings, he said.
Class action
Auckland schools Identified by the Ministry of Education as having leaky buildings:
Auckland Girls Grammar, Otahuhu Intermediate, Botany Downs Secondary College, Edendale Primary School, Glen Innes Primary School, Mt Albert Grammar, Macleans College, Murrays Bay Intermediate, Murrays Bay School, Northcote College, One Tree Hill College, Oteha Valley Primary School, Pakuranga College, Papatoetoe East School, Pinehill School, Pomaria School, Randwick Park, Rowandale School, Summerland Primary, Swanson School, Shelly Park School, Te Kura Kaupapa Maori O Nga Maungarongo.
Clarification: This story has been updated to reflect that Econi-corp holdings owed a duty of care to the Minister of Education, not to Glen Innes Primary.