Built to withstand - to build or not to build

This is a part of the Resilience feature

By Colin Barkus - 1 July 2025, Build 206

In some places, the risks posed by natural hazards might be so significant that building simply isn’t recommended. How do designers, builders and their clients decide?

It might be a dream clifftop home with fabulous sea views, a first family home in suburbia or an apartment block, office building or public facility in town – extreme natural events can put any building in virtually any part of the country at risk. Before any new project starts, those risks need to be understood – and sometimes a difficult call needs to be made.

Fortunately, reliable information is freely available to help designers, builders and their clients decide whether proceeding with a building project is wise.

CRESA and BRANZ risk assessment resources

With support from the public good science fund administered by the Ministry of Business, Innovation and Employment (MBIE) and the Building Research Levy, the Centre for Research Evaluation and Social Assessment (CRESA) has prepared Selecting a Site for Your Home – a simple, practical tool for assessing the risks posed to any building site by natural hazards (see For More below). Much of the advice provided in CRESA’s tool is also summarised in BRANZ bulletin BU700 Natural hazard information for building sites, available this July.

Start with the council

The BRANZ bulletin and CRESA tool recommend obtaining a land information memorandum (LIM) report from the local council as a starting point. From 1 July 2025, councils are required to include information known to them about natural hazards affecting land and the impacts of climate change that exacerbate natural hazards.

BRANZ also recommends obtaining a copy of the record of title for the site from Land Information New Zealand. The record of title will show what type of title applies to the site, which determines how the owner can act in certain situations – including after a natural disaster. The record of title might also include a notice (added under section 72 of the Building Act) about existing natural hazards, which could affect the owner’s ability to obtain insurance or a mortgage for the site. It’s well worth investigating before deciding whether to purchase or build.

CRESA’s tool suggests several additional questions to ask the council to aid the decision-making process:

Did the development require a resource consent or Resource Management Act hearing?
Has the site flooded more than once in the past?
Has the site been affected by slips and debris flows in the past?
Is the infrastructure in the area more than 25 years old?

Several councils offer free online hazard maps or viewers that allow users to enter a specific address and see any natural hazards to which the location is prone.

Note that, as well as providing this kind of information, councils can apply mandatory requirements to new buildings in identified hazard zones such as higher floor levels in flood-prone or low-lying areas. A consent for construction of a building can also be denied altogether based on the risks posed to the land or other nearby property by natural hazards. It’s advisable to ask about such requirements and restrictions early in the planning process.

Ask the developer

CRESA also recommends asking the developer, vendor or real estate agent some key questions before proceeding with a project:

Have risk assessments of the site been undertaken?
Have mitigation works been required in the development?
Has insurance on property or contents in the area ever been refused or been subject to higher premiums because of natural hazard risk?

Do your own research

Another useful source of information is the local library or museum. These facilities usually hold a comprehensive record of any past floods, storms or other severe natural events affecting the area and their impacts on the community such as prolonged supply disruptions to electricity, water or other utilities.

It’s also well worth consulting insurance companies directly about the scale and nature of natural hazard risks in the area and how they affect insurance cover and premiums.

The Natural Hazards Portal, maintained by the Natural Hazards Commission Toka Tū Ake (NHC), includes a searchable map showing insurance claims for natural events such as earthquakes, landslides and storms settled by NHC (previously EQC) since 1997. Users can enter an address or click on an individual property to see if there are settled EQCover or NHCover claims on it. While a property showing a settled claim is not necessarily a bad thing, looking up an address will reveal any history of claims and help inform about potential risks.

Finally, CRESA and BRANZ suggest having a good look around the site and its immediate surroundings. How close are streams, rivers and other waterways and what is the likelihood that a flood will affect the site? Are there trees sculpted by strong winds or large or broken trees nearby that might present a risk to the property in the future? Is there evidence of landslides and debris flows nearby? If it’s a coastal property, how far is it from the high tide line?

Regional and national sources

There’s also a wealth of regional and national information available from organisations such as GNS Science and NIWA. Free online resources show active fault lines, tsunami risk, climate norms and expected climate extremes. NIWA’s climate change projections show how the risk of flooding, coastal inundation and other weather-related hazards is likely to change in future in different parts of the country.

BRANZ Maps is another useful resource showing earthquake risk, climate and corrosion zones and expected rainfall intensities for specific addresses anywhere in the country.

Check with an expert

In some cases, particularly if the site has already been directly affected by a natural event, it’s worth commissioning a risk report from specialists.

If there may be geotechnical issues with a property – for example, if it’s on a steep slope or there’s evidence of landslides in the area – request a geotechnical report from a chartered professional engineer. The council may also require this as part of a consent application.