Page 57 - Build 153

Preparing for natural hazards
BRANZ has done a lot of work on the costs and bene ts of mitigating common natural hazards in housing. While some options are cost-e ective, others hardly justify the expenditure.
BY IAN PAGE, BRANZ PRINCIPAL ECONOMIST
Hazards
THE NEW ZEALAND BUILDING CODE has a variety of measures aimed at ensuring the health and safety of occupants in buildings. However, these don’t aim to prevent extensive damage that may make a house uninhabitable for a considerable time after a disaster.
Earthquakes resulted in design changes
An example was the Christchurch earthquakes where no lives were lost in housing, but some properties still aren’t repaired 5 years later.
Houses designed to NZS 3604:2011 Timber- framed housing generally performed well in these earthquakes. However, the extensive damage to foundations, claddings and linings revealed that unreinforced concrete founda- tions did not perform well structurally in soft ground, particularly in areas subject to liquefaction. Changes now require di erent detailing of slab oors.
But is there a case for going further and reducing material damage for other components?
Flooded properties.
Build 153 — April/May 2016 — 55
FEATURE SECTION
PHOTO – ALAN BLACKLOCK, NIWA