Posted on 23-12-2003
New
'leaky homes' standards not mandatory
By SIMON RANDALL
Councils, builders and architects do not have to comply with
new building standards, aimed at ending "leaky homes"
problems.
Untreated timber can still to be used in internal framing in
houses and in "low risk" outer walls under revised
standards announced by Standards New Zealand (SNZ) and backed
by the Building Industry Authority (BIA) today.
Although the revised standard specifies treated timber for
framing external walls when that framing is behind certain cladding
types, such as monolithic cladding systems, the BIA's official
citation of the standards does not make them mandatory.
Designers and builders are free to deviate from the standards
if they can satisfy local councils that buildings will be designed
and built without being susceptible to rot.
The BIA hoped councils would use the new standards as a benchmark,
authority chairman Barry Brown said today.
Although the BIA hoped the standards would see an end to leaky
homes being built, the authority could not offer a "100
per cent guarantee", he said.
"If buildings are well built they'll survive, if they're
not (well built) there's a good chance they won't," Mr
Brown said.
Under the standards, untreated timber, such as douglas fir,
can be used in walls deemed at "low risk" of leaking,
such as brick veneer buildings. It can be used in low-risk floor
framing, trusses and ceiling joints and interior construction.
But in a major change, untreated timber cannot be used in situations
where there was "significant risk" it would get wet
and therefore rot, SNZ general manager marketing Grant Thomas
said.
The standards were "less conservative" than proposed,
but comprehensive, Mr Brown said.
"The authority is not prepared to take risks with new
forms of construction at the expense of home owners."
Timber must now be colour-coded to ensure builders can easily
identify treatment levels, to reduce concerns about timber getting
mixed up on site.
Under the new standards, the cost of building a low-risk brick
house, which comprises a third of the market, would rise by
up to $2000. But the cost of building a higher risk house could
rise by $5000, Mr Brown said.
The BIA estimated the moves would benefit the economy by between
$94 million and $1.1 billion over the next 25 years.
Last Friday, the BIA confirmed the standards would be cited
as a means of compliance with the Building Code, taking effect
from April 1 2004.
"Although a considerable number of designers and builders
had already moved to using treated timber in some situations,
the publication of these standards, and the BIA's decision to
cite them, gives the whole industry clear guidelines on the
appropriate use of untreated and treated timber in houses,"
Mr Thomas said.
The New Zealand Forest Industries Council (NZFIC) today welcomed
the standards on use of treated timber, but remained concerned
about standards for treated timber in external frames.
"It is good to have this matter resolved," NZFIC
chief executive Stephen Jacobi said in a statement.
However, the industry was concerned the BIA was allowing use
of untreated radiata pine and douglas fir behind brick veneer
but required treatment in other situations, he said.
The decision was not justified by scientific analysis of the
leaky homes problem.
Building methods, not materials, had been the proven "culprit"
in leaky homes, Mr Jacobi said.
Mr Brown said the cladding standards aimed to give a second
line of defence for frames against moisture if outer walls leaked.
Douglas fir forest owners and sawmillers have said they will
continue to seek a judicial revue of BIA and SNZ decisions.
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