By ANDREW LAXON
Even well-built new houses are at risk of leaks and rot from modern building methods, says the expert who first alerted New Zealand to the leaky building crisis.
Philip O'Sullivan has warned that all houses containing both monolithic cladding and untreated timber framing are at risk because even
minor building faults can lead to disastrous results.
His comments would apply to about 40,000 homes built in the past five years, since untreated timber became the standard in new houses.
Mr O'Sullivan, a consultant with New Zealand's biggest leak-investigation firm, Prendos, described most modern houses as "film sets".
He said the public and the building industry had no idea that their protection against rot vanished with the abolition of compulsory timber treatment in 1996, and compared the change to downgrading road safety without informing the public.
"If you take the median barriers off the motorway and replace them with polystyrene the consequences of accidents would be huge, but driver behaviour would be the same.
"You're taking all the safety features away but not telling anyone. Everyone thinks it's still there."
Mr O'Sullivan said even small faults in houses with monolithic claddings - such as fibre cement, stucco and polystyrene-based systems - led to leaks.
The water could not escape once inside and quickly rotted the untreated timber framing.
Bad construction and design by builders and architects made the problem far worse but it was unfair to blame the problem solely on shoddy workmanship.
"Good builders still aren't getting it right because they're being given an impossible task and they think they can do it.
"The systems are fundamentally unsound ... so even a perfect house is going to have failures. It's intrinsic that they leak."
Steve Alexander, who runs the second-biggest leak investigation company, Alexander & Co, agreed with Mr O'Sullivan.
He said water also tended to soak through monolithic claddings and on to the timber framing, which added to the problem.
* If you have information about leaking buildings,
email the Herald or fax (09) 373-6421.
Further reading
Feature: Leaky buildings
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