Local
councils requiring earthquake strengthening when repairing existing buildings
cannot set standards beyond the 34 per cent limit set by regulations under the
Building Act. An attempt by Christchurch
City to set the seismic limit at 67 per cent of new building standard was struck
down by the High Court as invalid and in excess of its powers. A 34 per cent limit is the assessed seismic strength
required to support a building suffering an earthquake of one-third the
intensity that could be borne by a new building erected on that site.
In the aftermath of
Christchurch’s earthquakes, the local council has been setting new rules for
reinstatement of earthquake-damaged and earthquake-prone buildings. The Insurance Council, which represents
insurers covering some 95 per cent of New Zealand’s insurance cover, objected to
new city council rules which required buildings to be brought up to 67 per cent
of new building standard. The Insurance
Council said this would increase repair bills by hundreds of million dollars. The High Court was told that a rebuild of
earthquake damaged Canterbury University would cost an extra $140 million if a
67 per cent limit was set rather than 34 per cent.
In practice, building
owners want to see their buildings strengthened to a 67 per cent rating. Not only does this reduce risk, but also
improves the building value.
Post-earthquake rebuilds have been on hold while insurers have argued
over the level of seismic strengthening required. The level of danger created by the building,
the use to which it will be put and the cost of repairs are weighed by the city
council in giving approval to rebuild plans.
Justice Pankhurst said
the primary focus in the Building Act is to manage the likely risk of
earthquake-prone buildings collapsing causing injury or death. New buildings are required to meet 100 per
cent of the seismic strength required by regulations made under the Act. When repairing or reinstating existing
earthquake-prone buildings, they need only be brought up to 34% of the seismic
strength required for new buildings.
Councils cannot impose higher standards than those set under the
Building Act.
Insurance
Council v. Christchurch City – High Court (4.2.13)
13.004