Waterworld's ceiling is falling down

Hamilton City Council staff do not know what is wrong with Waterworld's failing ceiling tiles, two months after slinging nets to stop them falling on swimmers.

The acoustic tiles, part of a double-skinned suspended ceiling built during a $2 million renovation five years ago, began peeling away late last year.

An investigation into what is causing the problem - and what, if anything, can be done to fix it - is expected to be completed by staff next month.

City council property unit manager Ray Pooley told the Waikato Times it was too early to discuss possible remediation - or liability for any costs.

The 2007 upgrade involved renovating the existing roof steelwork and installing a double-layer suspended ceiling to stop moisture escape.

Air extraction and supply systems were upgraded and the entire 4000 sqm ceiling was replaced with an insulated barrier above an acoustic tile layer.

Poor air circulation and moisture escape through the ceiling was causing significant decay in the roof and walls, and corrosion on the diving tower.

Renovation contractor Watts & Hughes' construction director Mark Gutry said the company had been told of the issue about four months ago.

He said loss adjusters working for the council's insurers had requested a copy of commissioning data from the company for the air conditioning system and were looking into whether air flows were affecting the acoustic tile layer.

"We installed a specialised tile layer in accordance with the manufacturer's instructions," Mr Gutry said.

Mr Pooley said the report should be completed next month.