Information on Earthquake-Prone Buildings

Earthquake Prone Buildings in the West Coast Region

The Building (Earthquake-prone Buildings) Amendment Act 2016 (the Act) came into force on 1 July 2017 and contains major changes to the current system of identifying and remediating earthquake-prone buildings under the Building Act 2004 including a new national system for building identification and assessment and a publicly available national register of buildings that are earthquake-prone.

The majority of the West Coast region is in a high seismic zone (High Risk Z Factor > 0.3) and many commercial building owners have already provided Councils with earthquake reports and have upgraded their buildings to a higher level of strengthening than required to satisfy their clients and insurance companies.

There are a few, however, who have yet to provide a report and these owners will be targeted using the new identification policy for Earthquake Prone Buildings (EPB) set by the Ministry of Business, Innovation and Employment (MBIE) which comes into force on 1 July 2017.  Owners will have 12 months to provide an ISA (Initial Seismic Assessment) or DSA (Detailed Seismic Assessment) if the territorial authority (Council) considers the building to be earthquake-prone.

MBIE have set the minimum strengthening of commercial buildings at 34% of New Building Standards (NBS) but have a criteria for the most at risk buildings.

  • Unreinforced masonry buildings  (URM)
  • Pre 1976 buildings  - three or more stories
  • Pre 1935 buildings - one or two stories (excludes timber framed buildings)
  • Priority Buildings

The time frame in high risk areas for completing Seismic work on these buildings is 7.5 years (s.133 of the Act)

Using these criteria it would appear that 90% of buildings within the West Coast Region do not fit into the parameters of at risk buildings.  However, if any part of the construction system within a timber framed building or other type of construction material is considered to be ‘at risk’ (such as unreinforced concrete/ masonry chimneys or party and boundary walls) the territorial authority will also be requesting a report from these building owners.  An ISA may be sufficient, unless it identifies NBS lower than or close to 34% in which case a DSA will be required.

Timber framed buildings that show significant lack of lateral bracing (older buildings that have had internal walls removed to create larger open spaces or have large open frontages that unbalance the bracing) will also be asked to provide an earthquake report.

Territorial authorities must undertake a review of commercial buildings or any other buildings of relevant significance to identify any for which a report has yet to be provided and will notify these building owners that an ISA or a DSA report is required within one year of the review date.  This report must identify the parts of the building affected and the owner and Councils must then come to an agreement on the strengthening or removal over an agreed time frame.  All earthquake prone building strengthening building work must be undertaken with a building consent.                                                   

For any buildings where the report identifies a rating of less than 34% NBS Councils must issue an Earthquake-prone Building Notice (EPB) and a copy of this notice must also be displayed on the front of the premises.  

If no report is provided, then an EPB notice under s.133AL of the Building Amendment Act 2016 will be issued, with a copy fixed to the front of the premises in a prominent area, to notify the public that the building is classified as potentially earthquake prone.  A copy of this notice must also be issued to interested parties.  The territorial authority must also identify the building with the lowest rating i.e. EPB and proceed as if it is earthquake Prone.

Failure to comply may result in the territorial authority undertaking work at the owners’ expense.

Buildings identified as Earthquake Prone will also have to be entered into the national MBIE register which will be available to the public on line.

Please refer to the MBIE website for more information at: