The Ministry of Education is holding architects, designers and builders liable for the cost of repairs to nearly 90 leaky schools so far.
Legal action is under way for 87 of 309 schools dealing with leakiness caused by poor design, workmanship, and quality control, and materials failure.
A 2011-12 ministry survey estimated the approximate national repair bill could be up to $1.4 billion. Contractors are only liable for the cost if they are still solvent and did the work within the past 10 years.
Those businesses that are economically viable have been pursued by the ministry. Details remain confidential to protect commercial negotiations and cases before the courts, a spokeswoman said.
There are 25 legal cases pending from the 33 schools in Wellington and the lower North Island with leaky buildings. Wellington's repair bill is estimated at $13m.
"Where there is a potential claim, the ministry is pursuing all relevant parties that have had a contractual relationship with the ministry and/or board of trustees," a ministry spokeswoman said. Those contractors included architects, designers and builders.
Repair works on blocks that have been identified as having weathertightness issues are being undertaken on a priority basis, with 97 blocks under remediation construction.
The ministry was required to foot the bill to repair a leaky classroom and library discovered at Brooklyn School in 2010, because it fell just outside the 10-year limitation period.
A greenish black mould commonly found in leaky homes - known as stachybotrys - was found on the walls of a block of classrooms, but had since been removed.
Last year in one of the school's board of trustees newsletters, the board expressed frustration at the ministry's "ineptitude", saying its building issues had been "stalled yet again by the ministry's bureaucracy".
Principal Liz Rhodes now says it is exciting to see the school's repairs progressing well.
Other leaky schools without legal proceedings pending that the ministry could name are Kelburn Normal, Khandallah, Seatoun, West Park, Naenae College, and Tawa Intermediate.
- Fairfax Media
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