Council, 10 September 2010.

Earthquake-prone, dangerous and insanitary buildings policy 2010 [PDF, 764 KB].


  1. This Policy is different to that adopted on 10 September 2010. Certain passages under "item 2 Earthquake-Prone Buildings" have been deleted in order to comply with the High Court declaration which was made following the decision in Insurance Council of New Zealand v Christchurch City Council (2013) NZHC 51.
  2. On commencement of "The Building (Earthquake-prone Buildings) Amendment Act 2016", the references to earthquake-prone will be removed from the Council's Policy and the requirements for earthquake buildings will be as set in the Amendment Act. Commencement will occur no later than 13 May 2018.

The Christchurch City Council, in an extraordinary meeting on 10 September 2010, adopted the revised Earthquake-prone, Dangerous and Insanitary Buildings Policy.

The Council is required by law to have such a policy. It adopted its first in 2006, and reviewed and revised this in early 2010.  Consultation on its proposed revised policy was carried out from 30 March 2010 to 7 May 2010, before the September 4 earthquake. The Panel had met, and already made a decision which was due to be recommended to the Council for adoption at the end of September.

While the Council has general powers to deal with dangerous buildings, it becomes very complicated when buildings become dangerous as a result of an earthquake. The Panel hearing the policy had identified a gap in the current policy and in its report to Council proposed a new Section 2.3.6 to clarify how to handle known Earthquake-prone Buildings in the event that they were damaged by an earthquake and needed to be repaired.

The net result of the unanimously adopted policy is this:

  • It still only applies to those buildings defined as earthquake–prone.  (It does not apply to the average residential home. It does not affect the likes of chimney repairs).
  • Section 2.3.6 only applies to those buildings which have suffered damage in the earthquake which will require building consent to repair. If an “Earthquake-prone Building” is undamaged and does not need repair, the policy requires it to be seismically upgraded in accordance with the timeframes established in the policy.
  • The policy does not apply to a new building replacing one demolished by the earthquake – all new buildings must comply fully with the current building code requirements.
  • The policy applies equally to listed heritage buildings and buildings which are not listed.
  • The Council will encourage strengthening to at least 67% of the standard for a new building and will work closely with building owners to achieve sensible, safe outcomes.
  • The minimum level to remove the building from the Earthquake Prone Category is 34%.


Overview of Policy

What is the new policy?
This policy updates the policy adopted by the Council in 2006, as required by the Building Act 2004.  It sets out how the Council will perform its functions under the Act in relation to earthquake-prone, dangerous and insanitary buildings.  In relation to earthquake-prone buildings the policy aims to increase the strength of Christchurch buildings through the processes in the policy and the Building Act so, in future earthquakes, the damage to both people and property is minimised.  Stronger buildings will not only improve public safety, but will also provide greater resilience and a quicker recovery time after an earthquake.

What changes does the policy introduce?
The new policy encourages building owners of earthquake-prone buildings to strengthen their buildings to 67% of code.  Other changes include the introduction of time frames for different importance levels of buildings, clarifying the definition of significant alteration, requiring owners to take action if buildings are damaged in an earthquake and other minor changes.  There were no significant changes to the dangerous and insanitary buildings provisions in the policy.

When is the policy effective from?
The policy is effective immediately (from 10 September 2010) for any earthquake-prone building for which a building consent application is made that involves a significant alteration or repair to the building (this may include buildings damaged by the recent earthquakes). However, if the building was not damaged by the recent earthquakes or no building consent applications are made then owners have 15 to 30 years, from 1 July 2012, to complete the required earthquake strengthening work.
View the Earthquake-prone, Dangerous and Insanitary Buildings Policy in full

What buildings does this policy affect?
The earthquake-prone buildings section of the Policy will primarily affect buildings constructed prior to 1976.  Buildings constructed after that date are less likely to be earthquake-prone. It affects these buildings in two different ways, as follows:
• If an earthquake-prone building was damaged by the recent earthquakes, the policy affects the building immediately.
• If an earthquake-prone building was not damaged by the recent earthquakes, the policy will affect them from 1 July 2012.

What buildings are not affected by this policy?
• Buildings used wholly or mainly for residential purposes – unless the building comprises of two or more storeys and contains three or more household units.
• Buildings that were designed or strengthened to the 1976 NZS 4203 Building Codes and subsequent codes, unless they have a critical structural weakness.
• Isolated structures unlikely to collapse.
• Infrastructure assets covered by an Assets Management Plan such as infrastructure assets owned or controlled by the Council, Transit New Zealand or the owner of ‘works’ as defined in the Electricity Act 1992.


67% Strengthening Target

Is the new 67% earthquake strengthening standard a compulsory target for all earthquake-prone buildings?
No. The 67% earthquake strengthening standard is a target that the Council encourages building owners to meet. The Council will work closely with building owners to achieve sensible, safe outcomes that are economically feasible, and will strengthen the building to a level of at least 34%. The Council will also take into account heritage values of listed heritage buildings.

Does the new 67% strengthening target in the policy apply to all buildings?
No.  It applies only to buildings that are defined as earthquake-prone and applies equally to listed and unlisted heritage buildings.  It does not apply to the average residential home and does not relate to chimney repairs. 

Does this new policy apply to new buildings?
No. The policy does not apply to new buildings or a new building replacing an old building that was demolished as a result of the earthquake. All new buildings must be designed to withstand earthquakes and fully comply with the current Building Code requirements. An earthquake strengthening level under 100% is not considered acceptable for any new building.

If my commercial building already has an earthquake strength level above 33% of code what do I do?
If it is above 33% of code then your building is not an earthquake-prone building and the policy does not apply.  If it hasn’t been damaged, become dangerous or insanitary, and will still be used for the same business purpose as outlined in the Building Consent, then you do not need to do anything.


Earthquake damaged buildings

If my commercial building was damaged by the recent earthquakes what do I do?
Before you begin repairs on the building you will need to undertake a number of tasks as part of your Building Consent application process, as follows:-.
Check the most recent engineer’s report for your building and see what percentage level of earthquake strengthening the building meets under the Building Code. This information is usually on the last page of your engineer’s report in the ‘summary’ section. There may be a number of calculations on this page, along with a final percentage figure, indicating its earthquake strengthening level. If you are not sure you are looking at the correct figure, either double-check it with the original author of the report or ask a certified engineer to check it for you.

If the earthquake strengthening level is 34% or less you will need to get a certified engineer to assess your building and write a report for you to include in your Building Consent application. The engineer’s report, along with the repair plans and specifications, then need to go to the Christchurch City Council’s Building Consents Team as part of your Building Consent application. The Council will analyse the engineer’s report, and the rest of the information provided in your Building Consent application. The Council encourages building owners to prepare plans for their buildings to reach a strengthening level of 67%, but an earthquake-prone building must be strengthened to at least 34%.  If a building consent application does not increase the strength of an earthquake-prone building the Council will issue a section 124 notice to require the owner to strengthen their building (see below).

If the earthquake strength level of your building is between 34% and 67% (or higher) your building is not an earthquake-prone building and the policy does not apply.  Council would encourage you to consider strengthening the building to at least 67% as part of your repairs.

What do I do if my earthquake-prone building was damaged by the recent earthquakes but won’t be repaired until after 1 July 2012?
The policy provides that after 1 July 2012 the Council will categorise and prioritise earthquake-prone buildings into three different categories (Category A buildings will have 15 years to be earthquake strengthened, Category B will have 20 years and Category C buildings will have 30 years). Those time frames do not apply when a building consent application is received that involves a “significant alteration” (as defined in the policy).


Buildings Not Damaged by Earthquakes

If my commercial building is currently less than 34% earthquake strength but WAS NOT damaged by the recent earthquakes in 2010, what do I do?
Unless you plan on carrying out repairs or alterations to your building, you do not need to do anything at this stage. However, from 1 July 2012 the Christchurch City Council will begin reviewing council files in order to identify buildings that could be earthquake-prone. Owners will receive a letter from the Council informing them their building could be earthquake-prone and that further assessment will be needed.  Once the assessment has been completed the Council will either issue the building owner with a section 124 notice (if the building is deemed to be earthquake-prone and needs earthquake strengthening) or will inform the owner that the building meets the Building Code and no further earthquake strengthening needs to take place.

What is a section 124 notice?
A section 124 notice is a notification under the Building Act 2004 that the Council can issue. It allows the Council to:
(a) put up a hoarding or fence to prevent people from approaching the building nearer than is safe;
(b) attach in a prominent place on or adjacent to, the building a notice that warns people not to approach the building;
(c) give written notice requiring work to be carried out on the building.
(Note that additional powers have been given to Council to deal with earthquake-prone, dangerous and insanitary buildings in response to the earthquakes).
Please be aware that a person commits an offence if they fail to comply with a section 124 notice and could be liable to a fine not exceeding $200,000.

Will the Council issue me with a section 124 notice without any warning?
No. Before exercising its powers under section 124 of the Building Act, the Council will discuss options for action with owners, with a view to reaching a mutually acceptable approach for dealing with the problems identified. It is hoped this will result in the owner submitting a proposal to the council outlining their plans for the strengthening or removal of the earthquake-prone building. In the event that discussions do not result in a mutually acceptable approach and/or proposal, the Council will then serve a formal notice on the owner in accordance with section 124 of the Building Act 2004.


General Information

What type of building work will trigger a need to strengthen my earthquake-prone building?
When the Council receives a Building Consent application for building work on an earthquake-prone building that is structural, involves work costing over $50,000 or more than 25% of the rateable value of the building, then the Council will require that the building be strengthened.

What is the Council process for establishing and recording a building’s earthquake-prone status?
The Council process takes place in three stages, as follows:
1. Stage One: Identification of potentially earthquake-prone buildings from a review of Council files.
2. Stage Two: Initial assessment using the New Zealand Society of Earthquake Engineers’ (NZSEE’s) Initial Evaluation Procedure. The results from this initial assessment will be noted on the property file and in the Geographic (GIS) system.
3. Stage Three: Detailed assessment using the NZSEE’s detailed assessment method. The results from this detailed assessment will be noted on the property file and in the GIS system. At this stage a section 124 notice could be issued to the owner of the building giving them a certain amount of time to complete earthquake strengthening work.
Please be aware that not all buildings will go through either or both of Stages Two and Three. The undertaking of initial and detailed assessments is at the owner’s discretion, although this does not prevent the Council from carrying out an assessment at any time.

What if I disagree with the Council’s initial assessment or detailed assessment of my building?
You will be advised from the date of the initial letter (which advises you that your building is considered earthquake-prone), that you have 60 days to provide evidence that the building is not earthquake-prone. The Council will accept an initial assessment using the New Zealand Society of Earthquake Engineers’ (NZSEE’s) Initial Evaluation Procedure, or an equivalent method, as satisfactory evidence that a building is not earthquake-prone.

What does ‘Earthquake-Prone’ mean?
An earthquake-prone building is a building that:
• will have its ultimate capacity exceeded in a moderate earthquake, and
• would be likely to collapse causing injury or death to persons in the building or to persons on any other property; or cause damage to any other property.
An earthquake-prone building will generally have a strength that is less than 33% of the current seismic loading standard in New Zealand.

How many earthquake-prone buildings are there in Christchurch?
Prior to the earthquakes it was estimated there were potentially 7600 buildings in Christchurch that were ‘earthquake-prone’.

What type of buildings has the highest risk from earthquakes?
The buildings in Christchurch that were constructed before 1976 that have the highest risk of collapse in an earthquake are un-reinforced masonry buildings. However, refurbishment and redevelopment for new uses for these types of buildings has meant some of them are stronger than they once were.

Are there any earthquake-prone heritage buildings in Christchurch?
Prior to the earthquakes, there were approximately 490 heritage buildings that were earthquake-prone. Many heritage and character buildings sustained extensive damage in the earthquakes, and have since been demolished. The majority of heritage buildings in Christchurch were un-reinforced masonry (295) while 29 were reinforced concrete and 163 were timber-framed buildings.

What is considered a ‘moderate earthquake’?
A moderate earthquake, in relation to a building, is an earthquake that would generate shaking at the site of the building that is of the same duration as, but that is one-third as strong as the earthquake shaking (determined by normal measure of acceleration, velocity, and displacement) that would be used to design a new building at that site.


Earthquake prone buildings list

List of earthquake prone buildings 

The Council has received Detailed Engineering Reports (DEEs) from the Canterbury Earthquake Recovery Authority (CERA). Some of these buildings are listed as earthquake prone and have been put on the Council's Earthquake prone buildings register.

The Council expects to receive further DEEs over the next few years in relation to non residential and multi residential buildings across Christchurch. As a result the list of buildings on the register is expected to change regularly as more buildings are added, or buildings are strengthened or demolished. The Council recognises that many property owners are taking action to address problems associated with their building/s.

Useful information:

Guidance for engineers assessing the seismic performance of non-residential and multi-unit residential buildings in greater Christchurch - June 2012(external link).