Earthquake‑prone building reforms: Why Gisborne faces minimal change

The aftermath of Gisborne's 2007 earthquake. Changes to the earthquake-prone building system are not expected to result in major changes for Gisborne, where 22 buildings are registered as earthquake-prone. Photo / Gisborne Herald file – Brett Mead

The Government’s announced changes to the earthquake-prone building system are not expected to result in major changes in Gisborne, where 22 buildings are on the national earthquake-prone building register.

Other councils have hailed the changes, which are expected to save building owners across the nation $8.2 billion in remediation and demolition costs, and result in 2900 buildings out of 5800 being removed from the national register.

But Gisborne District Council building services manager Ian Petty told the Gisborne Herald he could foresee no real changes in the CBD “as our current momentum has meant all but a few CBD buildings remain with work to be done”.

“While we have had an earthquake-prone building register since 1993, there have been many buildings that were not on that register that have been strengthened by the owners without any push or enforcement from the council.

“Gisborne’s earthquake history, especially since the 2007 event, means that most people are aware of the risk that earthquakes pose and have kept the strengthening momentum up with little need for any push from the council,” Petty said.

Under existing legislation, the expected seismic performance of an existing building is compared with that of a new building. The result is then expressed as a percentage. A building assessed at less than 34% of the National Building Standard (NBS) must be either strengthened or demolished within a specific timeframe.

Under the new system, the NBS percentage ratings will be removed in favour of a “more proportionate risk-based” Earthquake Prone Buildings (EPB) system that reduces costs while addressing safety risks in the most vulnerable buildings located in medium and high seismic zones”, such as Gisborne.

Other regions with low seismic activity, such as Auckland and Northland, have been excluded from the new system.

Instead, EPBs will include concrete buildings that are three storeys or higher and those constructed with unreinforced masonry with unsecured facades and walls above public areas or neighbouring buildings.

There will be four levels of mitigation in the new system, being publicly listed on the register, facade securing, a targeted retrofit or a full retrofit.

Unreinforced masonry buildings under three storeys in small and rural towns – under 10,000 people – will no longer require remediation or warning notices.

The Government estimates 1440 buildings will face “more cost-effective remediation requirements”, while 840 will require no remedial work. Only about 80 buildings will still need a full retrofit.

Since the early 1990s Gisborne District Council “had been at the cutting edge when it comes to strengthening”, Petty said.

“Council has collaborated with the owners of buildings that have already been strengthened, working towards non-intrusive strengthening solutions, when possible, to maintain the important heritage characteristics of our buildings.”

The council was the first in New Zealand to work on an exemption policy for “the lovely rural brick churches” that are dotted throughout the region and that preservation ethos has extended to the buildings in the CBD.

“The changes promulgated by the Government appear to underline this approach and preserve the important heritage fabric of buildings in all of New Zealand while maintaining focus on the highest-risk buildings.”

Mayor Rehette Stoltz said she welcomed the Government’s announcement.

Clarity from the Government in categorisation and expectations helped the council address ongoing issues with buildings, especially in the CBD.

“I want to acknowledge the building owners who have completed earthquake strengthening to future-proof their assets,” she said.

“I am sure building owners will also appreciate more clarity on a way forward.”