Hazards
- Picture: APN Ltd
Some properties are exposed to toxic waste or increased risk of natural hazards such as earthquakes.
Before you buy or build, it’s worth checking whether your site is exposed to any of these risks.
Chemicals
Before you buy a property or start building on a site, it's worth finding out whether it has been used for anything that might create chemical hazards - for example:
- an orchard
- a timber treatment plant
- a chemical dump
- a landfill
- a petrol filling station
- a farm (there may be a risk of exposure to sheep dip, for example)
In most cases, it's best to steer clear of any site where there's a risk of chemical hazards. They may present significant health risks.
For former landfills, check with your local council about any safety issues. For example, at the edges of old landfills there can be leakage of hazardous methane gas.
Your local council should have information about a property's former uses. A Land Information Memorandum should have any information the council knows about chemical hazards relating to the site.
Other sources of information may include site or area photographs from your local library.
Earthquake
Earthquake risk will affect the structure and design of your home or renovation. In particular, exposure to earthquake risk will determine the amount of bracing your home needs to withstand the force of an earthquake.
New Zealand is divided into three earthquake zones (see map below). Your designer or engineer will consider the earthquake zone your property is in as part of the process of designing any building or extension.
For more detailed information, see the ConsumerBuild website’s page on environmental zones, or New Zealand Standard 3604:1999 Timber-framed buildings.
Flooding and erosion
A property may be more susceptible to flooding, erosion and subsidence if it has had substantial earthworks carried out, or substantial amounts of vegetation removed.
Before you buy or build, it’s worth checking whether your site is exposed to these risks. It’s also worth checking stormwater flows on your and neighbouring properties.
This may influence which parts of a site can be built on and the design and structure of any building you put up.
Your local council should have information about flood and erosion risks in your area. It’s worth obtaining a land information memorandum before you buy a site, and it may be worth getting an engineer’s report.
For more information on flood and erosion risks, see landforms and waterways.
Extreme weather
A property may be exposed to extreme weather such as high winds and heavy rain. For example, valleys can create a ‘wind tunnel’ effect increasing exposure to winds.
This can influence the design and structure of any home or extension you build on the site. For example, homes need sufficient bracing to withstand strong winds. High winds will also influence placement of windows and doors, and may influence the shape/structure of the roof.
For more information on climate risks, see climate.
More information
From Smarter Homes
From other sites
The local council’s land information memorandum for your property should contain information about any hazards that the council knows about. Consumerbuild’s Council finder web page has contact details for New Zealand local authorities.
You can buy New Zealand Standard 3604 through the Standards New Zealand website.
The National Institute of Water and Atmospheric Research’s natural hazards centre has information about hazards such as earthquakes and flooding.
The Landcare Research website has information about contaminated sites.
