A top-level inquiry is urging a return to traditional building methods to stop the epidemic of leaky buildings.
The independent report, initiated by the Building Industry Authority, recommends a return to traditional approaches to watertightness, such as installing a protective layer between the outer wall and frame.
Thereport found enough evidence of leaky building syndrome for the authority to take immediate action.
It will review the Building Code and draft clauses based on a traditional approach to weathertightness, and a forum of industry leaders will be organised to develop a solution.
In April the Herald published articles about the leaky building crisis. Thousands of new homes are believed to have serious leaks and rotting timber frames, creating a national repair bill estimated at $1 billion.
Sources said as many as one in 10 new homes - 2000 of the 20,000 built each year - are at risk.
The Herald found the causes included shoddy workmanship, untreated timber, declining building standards and the replacement of weatherboard and brick with new claddings.
The authority's chief executive, Bill Porteous, said traditional buildings also leaked, but the older claddings allowed water to escape or evaporate.
He said in new buildings it would be recommended that there was an inner membrane behind the outside wall to intercept the water before it got to the framing, and allow it to escape.
Registered Master Builder's Federation chief executive Chris Preston said other solutions would be to use treated timbers in areas likely to collect water, and cavities between the outer wall and the frame to allow moisture to escape.
The report has not established the exact number of buildings affected, but says more new houses are showing signs of water damage.
The houses typically affected were upmarket houses and multi-unit apartments in the medium price range.
